Interlaboratory Proficiency Test 10/2016

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3 REPORTS OF THE FINNISH ENVIRONMENT INSTITUTE 8 7 Interlaboratory Proficiency Test /6 Metals in waste water and recycled material Mirja Leivuori, Riitta Koivikko, Timo SaraAho, Teemu Näykki, Keijo Tervonen, Sari Lanteri, Ritva Väisänen and Markku Ilmakunnas SYKE Helsinki 7 Finnish Environment Institute

4 REPORTS OF THE FINNISH ENVIRONMENT INSTITUTE 8 7 Finnish Environment Institute SYKE Proftest SYKE Layout: Markku Ilmakunnas The publication is also available in the Internet: helda.helsinki.fi/syke ISBN (PDF) ISSN (Online) Author(s): Mirja Leivuori, Riitta Koivikko, Timo SaraAho, Teemu Näykki, Keijo Tervonen, Sari Lanteri, Ritva Väisänen and Markku Ilmakunnas Publisher and financier of publication: Finnish Environment Institute (SYKE) P.O. Box, FI5 Helsinki, Finland, Phone , syke.fi. Year of issue: 7

5 ABSTRACT Proftest SYKE carried out the proficiency test (PT) for analysis of metals in waste waters and fly ash from wood and recycled fuel in OctoberNovember 6. The measurands for synthetic sample as well as municipal and industrial waste water samples were: Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V and Zn. For the fly ash sample, the measurands were: As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V and Zn. In total 6 participants joined in the PT. In this proficiency test 9 % of the results were satisfactory when deviation of 5 % from the assigned value was accepted. Basically, either the metrologically traceable concentration, calculated concentration, the robust mean or the mean of the results reported by the participants was used as the assigned value for the measurands. The evaluation of the performance of the participants was carried out using the s. In some cases the evaluation of the performance was not possible e.g. due to the low number of the participants. There, when possible, D% and E n scores were calculated. Warm thanks to all the participants of this proficiency test! Keywords: water analysis, metals, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, V, Zn, water, waste water, fly ash, recycled fuel, environmental laboratories, proficiency test, interlaboratory comparisons TIIVISTELMÄ Proftest SYKE järjesti pätevyyskokeen ympäristönäytteitä analysoiville laboratorioille lokamarraskuussa 6. Pätevyyskokeessa määritettiin synteettisestä näytteestä, viemärilaitoksen ja teollisuuden jätevesistä Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V ja Zn sekä puun ja kierrätysmateriaalien polton lentotuhkasta As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V and Zn. Pätevyyskokeeseen osallistui yhteensä 6 osallistujaa. Koko tulosaineistossa hyväksyttäviä tuloksia oli 9 %, kun vertailuarvosta sallittiin 5 %:n poikkeama. Osallistujien pätevyyden arviointi tehtiin zarvojen avulla. Testisuureen vertailuarvona käytettiin metrologisesti jäljitettävää pitoisuutta, laskennallista pitoisuutta, osallistujien ilmoittamien tulosten robustia keskiarvoa tai keskiarvoa. Joissain tapauksissa tulosten vähäisen määrän vuoksi pätevyyden arviointi ei ollut mahdollista. Tällöin, mikäli mahdollista, laskettiin D% ja E n arvot. Kiitos pätevyyskokeen osallistujille! Avainsanat: vesianalyysi, metallit, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, V, Zn, lentotuhka, kierrätysmateriaali jätevesi, vesi ja ympäristölaboratoriot, pätevyyskoe, laboratorioiden välinen vertailumittaus SAMMANDRAG Proftest SYKE genomförde en provningsjämförelse i oktobernovember 6, som omfattade bestämningen av Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V, Zn i avloppssvatten och As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V, Zn bestämde i flygaska. Tillsammans 6 laboratorier deltog i jämförelsen. I jämförelsen var 9 % av alla resultaten tillfredsställande, när totalavvikelsen på 5 % från referensvärdet accepterades. Som referensvärde av analytens koncentration användes mest det metrologiska spårbara värdet, teoretiska värdet, robust medelvärdet eller medelvärdet av deltagarnas resultat. Resultaten värderades med hjälp av zvärden eller beräknade D% och E n värden. Ett varmt tack till alla deltagarna i testet! Nyckelord: vattenanalyser, metaller, Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, V, Zn, avloppssvatten, flygaska, återvunna bränslen, provningsjämförelse, vatten och miljölaboratorier

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7 CONTENTS Abstract Tiivistelmä Sammandrag... Introduction... 7 Organizing the proficiency test Responsibilities s Samples and delivery Homogeneity and stability studies Feedback from the proficiency test Processing the data Pretesting the data Assigned values Standard deviation for proficiency assesment and results evaluation... Results and conclusions.... Results.... Analytical methods Uncertainties of the results... 8 Evaluation of the results Summary... 6 Summary in Finnish... References... APPENDIX : s in the proficiency test... APPENDIX : Preparation of the samples... 5 APPENDIX : Homogeneity of the samples... 6 APPENDIX : Feedback from the proficiency test... 7 APPENDIX 5 : Evaluation of the assigned values and their uncertainties... 8 APPENDIX 6 : Terms in the results tables... APPENDIX 7 : Results of each participant... APPENDIX 8 : Summary of the s APPENDIX 9 : s in ascending order APPENDIX : Summary of D% and E n scores... 8 APPENDIX : Results grouped according to the methods... 8 APPENDIX : Significant differences in the results reported using different methods... APPENDIX : Estimation of the measurement uncertainties reported by the participants.. Proftest SYKE MET /6 5

8 6 Proftest SYKE MET /6

9 Introduction Proftest SYKE carried out the proficiency test (PT) for analysis of metals in waste waters and fly ash in October November 6 (MET /6). The measurands for synthetic sample and waste water samples were: Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V and Zn. For the fly ash sample, the measurands were: As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V and Zn. In total 6 participants took part in the PT. In the PT the results of Finnish laboratories providing environmental data for Finnish environmental authorities were evaluated. Additionally, other water and environmental laboratories were welcomed to participate in the proficiency test. Finnish Environment Institute (SYKE) is appointed National Reference Laboratory in the environmental sector in Finland. The duties of the reference laboratory include providing interlaboratory proficiency tests and other comparisons for analytical laboratories and other producers of environmental information. This proficiency test has been carried out under the scope of the SYKE reference laboratory and it provides an external quality evaluation between laboratory results and mutual comparability of analytical reliability. The proficiency test was carried out in accordance with the international guidelines ISO/IEC 7 [], ISO 58 [] and IUPAC Technical report []. The Proftest SYKE has been accredited by the Finnish Accreditation Service as a proficiency testing provider (PT, ISO/IEC 7, The organizing of this proficiency test is included in the accreditation scope with the exception of fly ash. Organizing the proficiency test. Responsibilities Organizer Proftest SYKE, Finnish Environment Institute (SYKE), Laboratory Centre Hakuninmaantie 6, FI Helsinki, Finland Phone: proftest@environment.fi The responsibilities in organizing the proficiency test Riitta Koivikko coordinator Mirja Leivuori substitute for coordinator Keijo Tervonen technical assistance Markku Ilmakunnas technical assistance Sari Lanteri technical assistance Ritva Väisänen technical assistance Timo SaraAho analytical expert (metals, IDICPMS) Teemu Näykki analytical expert (Hg, IDICPMS) Proftest SYKE MET /6 7

10 Cooperation partner Analytical expert Suvi Pöyhönen, The Water Protection (Fly ash) Association of the River Kokemäenjoki (KVVY), Subcontracting Fly ash homogenization, subsample divining and analysis: KVVY (T6, s In total 6 laboratories participated in this proficiency test (Appendix ), participants from Finland, one from Denmark, one from Sweden and two participants from Kyrgyzstan. Altogether 7 % of the participants used accredited analytical methods at least for a part of the measurements. For this proficiency test, the organizer has the codes 9 (SYKE, Helsinki, T, and 5 (KVVY, testing of fly ash sample) in the result tables.. Samples and delivery Four types of samples were delivered to the participants: synthetic, municipal and industrial waste water as well as fly ash samples. The synthetic sample AM was prepared from the NIST traceable commercial reference material produced by Inorganic Ventures. The synthetic sample AHg was prepared by diluting from the NIST traceable AccuTrace TM Reference Standard produced by AccuStandard, Inc. The sample preparation is described in details in the Appendix. The synthetic sample AM was acidified with nitric acid and the synthetic mercury sample AHg with the hydrochloric acid. The samples VM and VHg were municipal waste water with additions of single element standard solutions (AccuStandard for Hg and Merck CertiPUR for other elements, Appendix ). The industrial waste water samples TM (after analysis: TN no digestion / TY digestion with acid or with acid mixture) and THg for Hg measurements were prepared with additions of single element standard solutions (AccuStandard for Hg and Merck CertiPUR for other elements, Appendix ). This PT used the fly ash sample from the previous PT SYKE / [], here sample FM (after analysis: FC oxygen combustion (only Hg) / FN digestion with HNO / FO digestion with HNO + HCl / FT digestion with HNO + HF). The material was fly ash from recycled fuel and wood from Southern Finland, no addition of metals was needed for the fly ash test material. The fly ash samples were rehomogenized and redivided in the laboratory of Proftest SYKE. The samples were tested at the laboratory of The Water Protection Association of the River Kokemäenjoki in Tampere (KVVY). When preparing the samples, the purity of the used sample vessels was controlled. The randomly chosen sample vessels were filled with deionized water and the purity of the sample vessels was controlled after days by analyzing Cd, Cu, Hg, and Zn. According to the test results all used vessels fulfilled the purity requirements. 8 Proftest SYKE MET /6

11 The samples were delivered on 8 or October 6 to the international participants and on 5 October 6 to the national participants. The samples arrived to the participants mainly on 7 October 6. 7 received the samples on October 6. The samples were requested to be measured as follows: Mercury (AHg, VHg and THg) latest on November 6 The other samples latest on November 6 The results were requested to be reported latest on November 6 and mainly all participants delivered the results accordingly. One participant reported the results on November 6. The preliminary results were delivered to the participants via and via the electronic client interface ProftestWEB on December 6.. Homogeneity and stability studies The homogeneity of the waste water samples was tested by analyzing Cd, Cr, Hg, Pb, Se and Zn. More detailed information of homogeneity studies is shown in Appendix. According to the homogeneity test results, the samples were considered homogenous. The synthetic samples were prepared from traceable certified reference materials. However, homogeneity of these was checked by parallel measurements of three samples and they were considered homogenous. Based on the earlier similar proficiency tests the water samples are known to be stable over the given time period for the test. The homogeneity and stability of the fly ash sample was studied by analyzing As, Ba, Cd, Cr, Cu, Hg, Mo, Pb and V. More detailed information of homogeneity studies is shown in Appendix. The difference of the results from the homogeneity study and the result of the organizing laboratory (KVVY) during the test were compared to the criterion. s pt taking into account the total measurement uncertainties. The set criteria were fulfilled in all tested cases, thus the fly ash sample was considered homogenous and stable..5 Feedback from the proficiency test The feedback from the proficiency test is shown in Appendix. The comments from the participants mainly dealt with missing information in the covering letter of sample. The comments from the provider are mainly focused to the lacking conversancy to the given information with the samples. All the feedback is valuable and is exploited when improving the activities..6 Processing the data.6. Pretesting the data The normality of the data was tested by the KolmogorovSmirnov test. The outliers were rejected according to the Grubbs or Hampel test before calculating the mean. The results which differed more than 5 % or 5 times from the robust mean were rejected before the statistical Proftest SYKE MET /6 9

12 results handling. The replicate results were tested using the Cochrantest. If the result has been reported as below detection limit, it has not been included in the statistical calculations. More information about the statistical handling of the data is available from the Guide for participant [5]..6. Assigned values For the synthetic sample AM the NIST traceable calculated concentrations were used as the assigned value, with exception of Pb and Hg. The results based on isotope dilution (ID) ICPMS technique were used as assigned value for Hg and Pb in samples AHg, THg, VHg, AM, TN, and VM. The assigned value for Hg in the synthetic sample AHg based on an average of parallel IDICPMS measurements, while the assigned value for the samples VHg and THg based on an average of parallel measurements. The assigned value for Pb in the synthetic sample AM based on an average of 5 parallel IDICPMS measurements, while the assigned value for the samples TN and VM based on an average of parallel measurements. The IDICPMS method is accredited for soluble lead in synthetic and natural waters and for soluble mercury in synthetic, natural and waste water in the scope of calibration laboratory (K5; For the other samples and measurands the robust mean was used as the assigned value. When the number of results was low, the mean value was reported as the assigned value (n<, FC, FN, FO, FT, TY, Appendix 5). The robust mean or mean is not metrologically traceable assigned value. As it was not possible to have metrologically traceable assigned values, the robust means or means of the results were the best available values to be used as the assigned values. The reliability of the assigned value was statistically tested according to the IUPAC Technical report []. The expanded measurement uncertainty for the calculated assigned values was estimated using standard uncertainties associated with individual operations involved in the preparation of the sample. The main individual source of the uncertainty was the uncertainty of the concentration in the stock solution. For the metrologically traceable mercury and lead results, the uncertainty is the expanded measurement uncertainty of the IDICPMS method. When the robust mean or mean was used as the assigned value, the uncertainty was calculated using the robust standard deviation or standard deviation, respectively [, 5]. The uncertainty of the calculated and metrologically traceable assigned values for metals in the synthetic samples varied between.6 and %. When using the robust mean or mean of the participant results as the assigned value, the uncertainties of the assigned values were between. and % (Appendix 5). The assigned values have not been changed after reporting the preliminary results. Proftest SYKE MET /6

13 .6. Standard deviation for proficiency assessment and results evaluation The target value for the standard deviation for proficiency assessment was estimated on the basis of the measurand concentration, the results of homogeneity and stability tests, the uncertainty of the assigned value, and the longterm variation in the former proficiency tests. If the number of reported results was low or the deviation of the results was high (eg. FC: Hg; FN: As, Ba, Hg; FO: Ba, Hg; FT: As, Ba, Cd, Cr, Cu, Mo, Pb, V, Zn; TY: As), the total standard deviation and the assigned value are not set, and the proficiency estimation is not given. The target value for the standard deviation for proficiency assessment ( s pt, at the 95 % confidence interval) was set from % to 5 % depending on the measurements. The standard deviations of the proficiency assessment values have not been changed after reporting the preliminary results. When the number of reported results was low (n<6), the performance of the participant was estimated by means of D% values ( Difference ). D% values are calculated as the difference between the participant s result and the assigned value. D% value can be interpreted as the measurement error for that results to the extent to which the assigned value can be considered the reference quantity value. x i = participant s result, x pt = assigned value %= ( ) %, where Additionally, when the number of reported results was low and the uncertainty was set for the assigned value, the performance was estimated by means of E n scores ( Error, normalized ). These are used to evaluate the difference between the assigned value and participant s result within their claimed expanded uncertainty. E n scores are calculated: ( ) =, where x i = participant s result, x pt = assigned value, U i = the expanded uncertainty of a participant s result and U pt = the expanded uncertainty of the assigned value. Scores of E n, < E n <, should be taken as an indicator of successful performance when the uncertainties are valid. Whereas scores E n, or E n, could indicate a need to review the uncertainty estimates, or to correct a measurement issue. When using the robust mean as the assigned value, the reliability was tested according to the criterion u pt / s pt., where u pt is the standard uncertainty of the assigned value (the expanded uncertainty of the assigned value (U pt ) divided by ) and s pt is the standard deviation for proficiency assessment []. When testing the reliability of the assigned value the criterion was mainly fulfilled and the assigned values were considered reliable. Proftest SYKE MET /6

14 The reliability of the target value of the standard deviation and the corresponding was estimated by comparing the deviation for proficiency assessment (s pt ) with the robust standard deviation of the reported results (s rob, s) []. The criterion s rob / s pt <. was mainly fulfilled. In the following cases, the criterion for the reliability of the assigned value and/or for the reliability of the target value for the deviation was not met and, therefore, the evaluation of the performance is weakened in this proficiency test: Sample Measurement FO As,, Cr,, Mo,, Zn, FN Cd,, Mo, V TN Cu TY Cu,, Pb, Se VM Al Results and conclusions. Results The terms used in the result tables are listed in Appendix 6. The results and the performance of each participant are presented in Appendix 7 and the summary of the results in Table. The results of the replicate determinations are presented in Table. The summary of the s is shown in Appendix 8 and in Appendix 9 the s are shown in the ascending order. The summary of D% and E n scores are shown in Appendix. The reported results grouped by the used analytical methods with their expanded uncertainties (k=) are presented in Appendix. The robust standard deviations of the results mainly varied from. % to 68 % (Table ). The robust standard deviation of results was lower than % for 8 % of the results. Standard deviations higher than % apply mainly to the fly ash sample. For the waste water samples the robust standard deviations of the results varied from.9 % to 7 % and for the fly ash sample the variation was from. % to 68% (Table ). The robust standard deviations for waste water samples were approximately in the same range as in the previous similar proficiency test Proftest SYKE MET 8/5 [6], where the deviations varied from. % to 7.5 %. Proftest SYKE MET /6

15 Table. The summary of the results in the proficiency test MET /6. Measurand Sample Unit Assigned value Mean Rob. mean Median SD rob SD rob % x spt % n (all) Acc z % Al AM TN TY VM As AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Ba FN mg/kg FO mg/kg FT mg/kg Cd AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Co AM TN TY VM Cr AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Cu AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Fe AM TN TY VM Proftest SYKE MET /6

16 Table. The summary of the results in the proficiency test MET /6. Measurand Sample Unit Assigned value Mean Rob. mean Median SD rob SD rob % x spt % n (all) Acc z % Hg AHg FC mg/kg FN mg/kg FO mg/kg... 7 THg VHg Mn AM TN TY VM Mo FN mg/kg FO mg/kg FT mg/kg Ni AM TN TY VM Pb AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Se AM TN TY VM V AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Zn AM FN mg/kg FO mg/kg FT mg/kg TN TY VM Rob. mean: the robust mean, SD rob: the robust standard deviation, SD rob %: the robust standard deviation as percent, s pt %: the total standard deviation for proficiency assessment at the 95 % confidence interval, Acc z %: the results (%), where z, n(all): the total number of the participants. Proftest SYKE MET /6

17 In this PT the participants were requested to report duplicate results for all measurements. The participants reported the replicates with the exception of the participant. The results of the replicate determinations based on the ANOVA statistical handling are presented in Table. The estimation of the robustness of the methods could be done by the ratio s b /s w, which should not be exceeded for robust methods. However, in many cases the robustness exceeded the value ; varied between.5 and 5 (Table ). Table. The summary of repeatability on the basis of duplicate determinations (ANOVA) statistics. Measurand Sample Unit Assigned value Mean sw sb st sw% sb% st% sb/sw Al AM TN TY VM As AM FN mg/kg FO mg/kg TN TY VM Ba FN mg/kg FO mg/kg Cd AM FN mg/kg FO mg/kg TN TY VM Co AM TN TY VM Cr AM FN mg/kg FO mg/kg TN TY VM Cu AM FN mg/kg FO mg/kg TN TY VM Fe AM TN TY VM Proftest SYKE MET /6 5

18 Table. The summary of repeatability on the basis of duplicate determinations (ANOVA) statistics. Measurand Sample Unit Assigned value Mean sw sb st sw% sb% st% sb/sw Hg AHg FC mg/kg FN mg/kg FO mg/kg THg VHg Mn AM TN TY VM Mo FN mg/kg FO mg/kg Ni AM TN TY VM Pb AM FN mg/kg FN mg/kg FO mg/kg TN TY VM Se AM TN TY VM V AM FN mg/kg FO mg/kg TN TY VM Zn AM FN mg/kg FO mg/kg TN TY VM Ass.val.: assigned value; s w : repeatability standard error; s b : between participants standard error; s t : reproducibility standard error. 6 Proftest SYKE MET /6

19 . Analytical methods The participants were allowed to use different analytical methods for the measurements in the PT. The used analytical methods and results of the participants grouped by methods are shown in more detail in Appendix. The statistical comparison of the analytical methods was possible for the data where the number of the results was 5. Effect of sample pretreatment on elemental concentrations in waste waters Elements in waste water were mainly measured from acidified samples without sample pretreatment with the exception of the industrial waste water sample (TN/TY). More than half of the participant measured the acidified industrial waste water without sample pretreatment (TN), and the other participants measured the industrial waste water after acid digestion (TY). The results of these samples were evaluated separately (Appendix ). The difference between the average concentrations of elements measured by different sample pretreatment methods was tested using the ttest. Statistically significant difference was not observed for metal analyses. For an unfiltered waste water sample the results are expected, acid digestion should give similar or in some cases higher results than without digestion. Effect of sample pretreatment on elemental concentrations in fly ash sample Elements in the fly ash sample were measured mainly after acid digestion (FN/FO). In average, 55 % of the participants measured the fly ash sample after aqua regia digestion (FO), and the other participants measured the sample mainly after nitric acid digestion (FN). Two participants measured the fly ash sample after nitric acid and hydrofluoric acid digestion (FT). The results of these were evaluated separately (Appendix ). The difference between the average concentrations of elements measured by different acid digestion was tested using the ttest. Statistically significant difference was observed for Cr analyses. Nitric acid digestion gave significantly higher results compared to the aqua regia digestion approach (Appendix ). Noticeable was also that digestion with hydrofluoric acid increase the concentration of chromium (Table, Appendix ). This is evident also for copper, lead and zinc (Table ). The digestion method in general can highly influence the recoveries depending on sample matrix, digestion temperature and hold times, as well the sample weight and acid amount ratio. Effect of measurement methods on elemental results The most commonly used analytical method was ICPMS and ICPOES. FAAS or GAAS techniques were used by one participant for some measurements (Appendix ). The difference between the average concentrations of metals measured by different measurement methods was tested using the ttest. Statistically significant differences were observed for Al, Mn and Ni analysis of the synthetic sample AM. For Al analysis ICPMS technique gave higher results than ICPOES technique, while for Mn and Ni ICPMS technique gave smaller results than ICPOES technique (Appendix ). ICPMS is in most cases the technique of preference due to its superior detection capabilities compared to other techniques when low concentrations are to be measured. As a general note, a Proftest SYKE MET /6 7

20 low recovery may be an indication of loss of analyte which can occur during sample pretreatment (e.g. volatilization during acid digestion) or measurement (e.g. GAAS analysis). It may also be caused by incorrect background correction (ICPOES) or matrix effects. Recoveries that are too high may be caused by spectral interferences (overlapping wavelengths in emission spectrometry, polyatomic or isobaric interferences in mass spectrometry), matrix effects or contamination. Matrix effects can often be overcome by matrix matching the calibration standards, however this is often difficult with environmental samples since the elemental concentrations vary a lot even within the same sample type. Effect of measurement methods on mercury results For the analysis of mercury, ICPMS was the most often used method of analysis following by CVAFS. CVAAS or direct combustion technique was used one to two participants. One participant reported mercury results by CVICPMS technique (Appendix ). For the fly ash sample, aqua regia digestion (FO) was most commonly used, followed by nitric acid digestion (FN). Three participant analysed mercury from the fly ash sample with direct oxygen combustion (FC). Based on visual estimation no clear differences between the used methods of measurement or digestion could be concluded (Appendix ). Like most other metal determinations, mercury results are affected by the digestion procedures used (acids and oxidation reagents used, their concentration, amounts and purities, digestion temperature and time). For water samples hydrochloric acid is recommended for sample preservation and BrCl is recommended for oxidation of mercury species. Different cold vapour techniques usually give fairly similar results provided that the pretreatment is appropriate. CVAFS and CVICPMS have superior detection limits compared to CVAAS.. Uncertainties of the results In all 65 % of the participants reported the expanded uncertainties (k=) with their results for at least some of their results (Table, Appendix ). The range of the reported uncertainties varied between the measurements and the sample types. As can be seen in Table, many of the participants have clearly under or overestimated their expanded (k=) measurement uncertainty. Expanded measurement uncertainty below 5% is not common for routine laboratories. Also measurement uncertainty over 5% should not exist, unless the measured concentration is near to the limit of quantification. In order to promote the enhancement of environmental measurements quality standards and traceability, the national quality recommendations for data entered into water quality registers have been published in Finland [7]. The recommendations for measurement uncertainties for most of the tested measurands in waste water are %. In this proficiency test some of the participants had their measurement uncertainties within these limits, while some did not achieve them. Harmonization of the uncertainties estimation should be continued. Several approaches were used for estimating of measurement uncertainty (Appendix ). The most used approach was based on the data obtained from method validation, followed by the 8 Proftest SYKE MET /6

21 Table. The range of the expanded measurement uncertainties (k=, U%) reported by the participants. Analyte AM / AHg % FC / FN / FO / FT % VM / VHg % TN / THg % TY % Al 5 5 As 55 Ba 8 Cd Co 5 Cr Cu Fe Hg 6 5 Mn Mo Ni 57 Pb 5 5 Se V Zn approach based on the internal quality data with sample replicates. At maximum four participants used MUkit measurement uncertainty software for the estimation of their uncertainties. The free software is available on the webpage: [8]. Generally, the used approach for estimating measurement uncertainty did not make definite impact on the uncertainty estimates. Evaluation of the results The evaluation of the participants was based on the s (Appendix 6). The evaluation of the participants was based on the z and E n scores, which were interpreted as follows: Criteria Performance z Satisfactory < z < Questionable z Unsatisfactory. < En <. Satisfactory En. or En. Unsatisfactory In total, 9 % of the results were satisfactory, when deviation of 5 % from the assigned value was accepted (Appendix 8). Altogether 7 % of the participants used accredited analytical methods at least for a part of the measurements and 86 % of their results were satisfactory. The summary of the performance evaluation and comparison to the previous performance is presented in Table. In the previous similar PT, Proftest SYKE MET 8/5 [6], the performance was satisfactory for 9 % of the all participants. Based on E n scores 8 % of arsenic results in the samples FN and TY was satisfactory (Appendix ). Proftest SYKE MET /6 9

22 Table. Summary of the performance evaluation in the proficiency test MET /6. Sample Satisfactory results (%) Accepted deviation from the assigned value (%) Remarks AM / AHg 9/75 Generally good performance, but some difficulties in measurements for Hg, < 8% satisfactory results. In the MET 8/5 the performance was satisfactory for 89/85 % of the results [6]. FN / FO FN:As 9/9 En score: 8 5 Only approximate assessment for: FO: As, Cr, Mo, Zn; FN: Cd High uncertainty of the assigned value: FN: Mo, V Due to low number of results FC: Hg; FN: As, Ba, Hg; FO:Ba, Hg and FT:all measurands were not evaluated based on. For As in the sample FN En score evaluation was performed. Difficulties in measurements for FO: Zn, < 8% satisfactory results. TN / THg 9/76 5 Difficulties in measurements for Hg, < 8% satisfactory results. Somewhat approximate performance evaluation for Cu. In the MET 8/5 the performance was satisfactory for 9/85 % of the results [6]. TY 95 5 Difficulties in measurements for Zn, < 8% satisfactory results. Somewhat approximate performance evaluation for Cu, Pb, Se. TY:As En score: 8 Due to low number of the results TY: As was not evaluated based on, but based on En scores evaluation was performed. In the MET 8/5 the performance was satisfactory for 9 % of the results [6]. VM / VHg 9/88 5 Somewhat approximate performance evaluation for Al. In the MET 8/5 the performance was satisfactory for 89/8 % of the results [6]. D%scores deviated between and %; 7 % of the values were below % and % of the values were between and %; 5 % of the values were higher than % (bolded in Appendix ). In average, the satisfactory results varied between 75 % and 95 % for the tested sample types (Table ). The number of satisfactory results in the synthetic sample AM was the lowest for Hg 75 %, which was lower than in 5, when 85 % of results were satisfactory with the same accepted deviation ( %) from the assigned value [6]. The fly ash sample turned out to be challenging for many measurands and the number of participants analysing the sample was low. The performance evaluation for some measurands of the fly ash sample FM is only approximate due to the weakness of the reliability of the assigned value, the target value for total deviation and the reliability of the corresponding z score (Table ). For the fly ash sample, standard deviations of 5 % from the assigned value were accepted. Of the results obtained after nitric acid digestion (FN), 9 % of the results were satisfactory when the standard deviation of 5 % from the assigned value was Proftest SYKE MET /6

23 accepted. The fly ash sample from recycled fuel and wood was not tested in the previous proficiency tests. For the industrial waste water sample (TN/TY and THg) the satisfactory results varied between 76 and 95 %, when deviations of % from the assigned value were accepted. Difficulties were noticed in measurements of Hg and Zn in the sample TY. For Cd, Fe and Mn in the sample TN and for Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, and V in the sample TY all the results were satisfactory. For the municipal waste water sample VM all results for Co, Cr and Cu were satisfactory. For Hg in the waste water THg the number of satisfactory results (76 %) was lower than in 5, when 85 % of results were satisfactory with the same accepted deviation ( %) from the assigned value [6]. 5 Summary Proftest SYKE carried out the proficiency test (PT) for analysis of elements in waste waters and recycled fuel (fly ash) in OctoberNovember 6 (MET /6). The measurands for synthetic sample and waste water samples were: Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V, and Zn. For the fly ash sample, the measurands were: As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V, and Zn. Four sample types were: synthetic, municipal and industrial effluents as well as fly ash sample. In total 6 laboratories participated in the PT. For the synthetic sample AM the NIST traceable calculated concentrations were used as the assigned values with exception of Pb. For Hg and Pb (AHg, THg, VHg, AM, TN, VM, respectively) the assigned values based on the metrologically traceable isotope dilution technique (IDICPMS) results were used. For other samples and measurements the robust mean or mean value was used as the assigned value. The uncertainty for the assigned value was estimated at the 95 % confidence interval and it was between.6 and % for the calculated and metrologically traceable assigned values and for assigned values based on the robust mean or mean it was between. %. The evaluation of the performance was based on the s, which were calculated using the standard deviation for proficiency assessment at 95 % confidence level. In this proficiency test 9 % of the data was regarded to be satisfactory when the result was accepted to deviate from the assigned value to 5 %. About 7 % of the participants used accredited methods and 86 % of their results were satisfactory. Proftest SYKE MET /6

24 6 Summary in Finnish Proftest SYKE järjesti jätevesiä ja kierrätysmateriaalien polton lentotuhkasta analysoiville laboratorioille pätevyyskokeen lokamarraskuussa 6 (MET /6). Pätevyyskokeessa määritettiin synteettisestä näytteestä, viemärilaitoksen ja teollisuuden jätevesistä Al, As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, Se, V ja Zn sekä kierrätysmateriaalien polton lentotuhkasta As, Ba, Cd, Cr, Cu, Hg, Mo, Pb, V and Zn. Pätevyyskokeeseen osallistui yhteensä 6 laboratoriota. Mittaussuureen vertailuarvona käytettiin laskennallista pitoisuutta, osallistujien tulosten robustia keskiarvoa tai keskiarvoa. Lyijylle ja elohopealle käytettiin metrologisesti jäljitettävää tavoitearvoa osassa testinäytteistä. Vertailuarvolle laskettiin mittausepävarmuus 95 % luottamusvälillä. Vertailuarvon laajennettu epävarmuus oli,6 % laskennallista tai metrologisesti jäljitettävää pitoisuutta vertailuarvona käytettäessä ja muilla välillä, %. Pätevyyden arviointi tehtiin zarvon avulla ja tulosten sallittiin poiketa vertailuarvosta 5 %. Koko aineistossa hyväksyttäviä tuloksia oli 9 %. Noin 7 % osallistujista käytti akkreditoituja määritysmenetelmiä ja näistä tuloksista oli hyväksyttäviä 86 %. Proftest SYKE MET /6

25 REFERENCES. SFSEN ISO/IEC 7,. Conformity assessment General requirements for Proficiency Testing.. ISO 58, 5. Statistical methods for use in proficiency testing by interlaboratory comparisons.. Thompson, M., Ellison, S. L. R., Wood, R., 6. The International Harmonized Protocol for the Proficiency Testing of Analytical Chemistry laboratories (IUPAC Technical report). Pure Appl. Chem. 78: 596, Björklöf, K., KorhonenYlönen, K., Kaasalainen, M., Leivuori, M., Väntsi, S., Lanteri, S. and Ilmakunnas, M. Proficiency Test SYKE /. Leaching testing of solid waste sample. Reports of Finnish Environment Institute9/. 6pp. Helsinki Proftest SYKE Guide for laboratories: Current proficiency test ECE96D8C%7D/ Koivikko, R., Leivuori, M., SaraAho, T., Näykki, T., Tervonen, K., Lanteri, S., Väisänen, R. and Ilmakunnas, M. 6. Interlaboratory Proficiency Test 8/5. Metals in waste water and sludge. Reports of the Finnish Environment Institute /6. 5 pp. Helsinki Näykki, T., Kyröläinen, H., Witick, A., Mäkinen, I. Pehkonen, R., Väisänen, T., Sainio, P. ja Luotola M.. Laatusuositukset ympäristöhallinnon vedenlaaturekistereihin vietävälle tiedolle: Vesistä tehtävien analyyttien määritysrajat, mittausepävarmuudet sekä säilytysajat ja tavat. (Quality recommendations for data entered into the environmental administration s water quality registers: Quantification limits, measurement uncertainties, strorage times and methods associated with analytes determined from waters). Ympäristöhallinnon ohjeita /. (Environmental administration Guidelines /). 5 pp Näykki, T., Virtanen, A. and Leito, I.,. Software support for the Nordtest method of measurement uncertainty evaluation. Accred. Qual. Assur. 7: 66. MUkit website: 9. Magnusson, B. Näykki. T., Hovind, H. and Krysell, M.,. Handbook for Calculation of Measurement Uncertainty in Environmental Laboratories. NT Technical Report 57. Nordtest.. Ellison, S., L., R. and Williams, A. (Eds). () Eurachem/CITAC guide: Quantifying Uncertainty in Analytical Measurement, Third edition, ISBN ISO/IEC Guide 98:8. Uncertainty of measurement Part : Guide to the expression of uncertainty in measurement (GUM: 995). Proftest SYKE MET /6

26 APPENDIX (/) APPENDIX : s in the proficiency test Country Denmark Finland Kyrgyz Republic Sweden Force Technology, Holstebro, Denmark Ahma ympäristö Oy, Oulu Boliden Harjavalta Oy Boliden Kokkola Oy Ekokem Oy Ab, Riihimäki Freeport Cobalt Oy Huntsman P&A Finland Oy, Analyyttinen laboratorio Pori KCL Kymen Laboratorio Oy Kokemäenjoen vesistön vesiensuojeluyhdistys ry, Tampere Labtium Oy, Jyväskylä Labtium Oy, Kuopio LounaisSuomen vesi ja ympäristötukimus Oy, Turku Metropolilab Oy Nab Labs Oy / Ambiotica Jyväskylä Norilsk Nickel Harjavalta Oy Novalab Oy Outokumpu Stainless Oy, Tutkimuskeskus, Tornio Ramboll Finland Oy, Ramboll Analytics, Lahti SavoKarjalan Ympäristötutkimus Oy, Kuopio SGS Inspection Services Oy, Kotka SSAB Europe Oy, Analyysilaboratorio, Hämeenlinna SYKE Ympäristökemia Helsinki UPM Tutkimuskeskus, Lappeenranta SAEPF, EMA Laboratory, Bishkek, Kyrgyz Republic SAEPF, IssykKulNaryn, CholponAta City, Kyrgyz Republic Eurofins Environment testing Sweden AB, Lidköping Proftest SYKE MET /6

27 APPENDIX (/) APPENDIX : Preparation of the samples The synthetic samples AM was prepared by diluting from the NIST traceable certified reference materials produced by Inorganic Ventures. The synthetic sample AHg was prepared by diluting from the NIST traceable AccuTrace TM Reference Standard produced by AccuStandard, Inc. The water samples VM, TM (TN/TY), VHg and THg were prepared by adding some separate metal solutions (Merck CertiPUR or AccuStandard) into the original water sample, if the original concentration was not high enough. Al As Ba Cd Co Cr Cu Fe Mn Analyte Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value Original Dilution Addition Ass. value AM VM TN/TY 86 / / / / / / / 6 5 8/ 87 Measurand Mo Original Dilution Addition Ass. value Ni Original Dilution Addition Ass. value Pb Original Dilution Addition Ass. value Se Original Dilution Addition Ass. value V Original Dilution Addition Ass. value Zn Original Dilution Addition Ass. value Measurand Hg Original Dilution Addition Ass. value AM 7 7, ,6 6 6, ,9 5 5 AHg.6,59 Original = the original concentration Dilution = the ratio of dilution Addition = the addition concentration Ass. value = the assigned value VM 8,5 8,5,,,6, 7, 7,6,,7 8, VHg,6,86 5, TN/TY 8 9,8/ 9,9,76 8 8,/ 78,5, 7,/,6 7, 98 7/ 7 8/ 5 THg,,, Proftest SYKE MET /6 5

28 APPENDIX (/) APPENDIX : Homogeneity of the samples Homogeneity was tested from duplicate measurements of selected measurement from three to six samples of each sample types (see table below). Criteria for homogeneity s a /s h <.5 and s sam <c, where s h = standard deviation for testing of homogeneity s a = analytical deviation, standard deviation of the results within sub samples s sam = betweensample deviation, standard deviation of the results between sub samples c = F s all + F s a, where s all = (. s h ) Measurement/ sample F and F are constants of F distribution derived from the standard statistical tables for the tested number of samples [, ]. Concentration [] [mg/kg] n sh % sh sa sa/sh Is sa/sh<.5? Cd/VM Yes.. Yes Cr/VM Yes. Yes Se/ VM Yes. Yes Zn/ VM Yes.8 Yes Cd/TM Yes..9 Yes Cr/ TM Yes..79 Yes Se/ TM Yes.9.7 Yes Zn/TM Yes.9.6 Yes As/FM Yes.8 Yes Ba/FM Yes 9869 Yes Cd/FM Yes.99 Yes Cr/FM..6.6 Yes 5 9 Yes Cu/FM Yes 9. Yes Hg/FM Yes Yes Mo/FM Yes.9 Yes Pb/FM Yes 95.8 Yes ssam c Is ssam <c? V/FM Yes 6. Yes IDICPMS testing Hg/VHg* Yes.. Yes Hg/THg* Yes..5 Yes Pb/VM* Yes.. Yes Pb/TM* Yes.5.6 Yes *) result based on the IDICPMS measurement Conclusion: The criteria were fulfilled for the tested measurands and the samples were regarded as homogenous 6 Proftest SYKE MET /6

29 APPENDIX (/) APPENDIX : Feedback from the proficiency test FEEDBACK FROM THE PARTICIPANTS Comments on technical excecution Action / Proftest All The sample codes for sample TM were missing in the sample letter. The codes were informed later. In the future PTs the provider will be more careful with the given information. FEEDBACK TO THE PARTICIPANTS Comments 6 The participant reported only one result in their dataset for some samples and measurands, though replicate results were requested. These results were not included in the calculation of assigned values and s were not calculated. The provider recommends the participant to follow the given guidelines.,, 5,, For these participants the deviation of replicate measurements for some measurands and samples,, 7, were high and their results were Cochran outliers. The provider recommends the participants to 8,,, validate their deviation of replicate measurements., 6 Proftest SYKE MET /6 7

30 APPENDIX 5 (/) APPENDIX 5: Evaluation of the assigned values and their uncertainties Measurand Sample Unit Assigned value Upt Upt, % Evaluation method of assigned value upt/spt Al AM Calculated value.7 TN 6. Robust mean.7 TY Mean.8 VM 9 7. Robust mean.5 As AM Calculated value. FN mg/kg Mean FO mg/kg Mean.8 FT mg/kg 7.6 Mean TN 5. Robust mean. TY 6. Mean VM Robust mean. Ba FN mg/kg 55 Mean FO mg/kg Mean FT mg/kg Mean Cd AM Calculated value.5 FN mg/kg... Mean.5 FO mg/kg Mean. FT mg/kg 9.8 Mean TN Robust mean.9 TY Mean.9 VM.8.5. Robust mean. Co AM Calculated value.6 TN Robust mean.8 TY Mean. VM...7 Robust mean.5 Cr AM Calculated value.7 FN mg/kg Mean. FO mg/kg Mean.9 FT mg/kg 9 Mean TN 6 6. Robust mean.7 TY Mean.5 VM..5. Robust mean.8 Cu AM Calculated value.6 FN mg/kg 75. Mean.9 FO mg/kg Mean. FT mg/kg 95 Mean TN Robust mean.5 TY Mean.5 VM Robust mean.8 Fe AM Calculated value.6 TN. Robust mean.9 TY 6. Mean.7 VM 6 6. Robust mean.7 Hg AHg.59.. IDICPMS.5 FC mg/kg.8 Mean FN mg/kg.99 Mean 8 Proftest SYKE MET /6

31 APPENDIX 5 (/) Measurand Sample Unit Assigned value Upt Upt, % Evaluation method of assigned value upt/spt Hg FO mg/kg. Mean THg... IDICPMS.5 VHg IDICPMS.5 Mn AM 5.6 Calculated value.6 TN 8 7. Robust mean.7 TY Mean.7 VM 88. Robust mean. Mo FN mg/kg 7... Mean.8 FO mg/kg Mean. FT mg/kg.6 Mean FT mg/kg.6 Mean Ni AM Calculated value.6 TN Robust mean. TY Mean.8 VM Robust mean. Pb AM IDICPMS. FN mg/kg 9. Mean.7 FO mg/kg. Mean.5 FT mg/kg 75 Mean TN IDICPMS. TY Mean.7 VM.6.. IDICPMS. Se AM Calculated value.8 TN..8. Robust mean.9 TY Mean.5 VM Robust mean.5 V AM Calculated value.6 FN mg/kg Mean. FO mg/kg Mean.5 FT mg/kg 8. Mean TN Robust mean.5 TY 7. Mean.7 VM.7.6. Robust mean.9 Zn AM 5.6 Calculated value.6 FN mg/kg 75. Mean. FO mg/kg 9 6. Mean. FT mg/kg 86 Mean TN Robust mean. TY 5. Mean. VM..7. Robust mean.9 U pt = Expanded uncertainty of the assigned value Criterion for reliability of the assigned value u pt/s pt <., where s pt= target value of the standard deviation for proficiency assessment u pt= standard uncertainty of the assigned value If u pt/s pt <., the assigned value is reliable and the s are qualified. Proftest SYKE MET /6 9

32 APPENDIX 6 (/) APPENDIX 6: Terms in the results tables Results of each participant Measurand The tested parameter Sample The code of the sample Calculated as follows: z = (x i x pt )/s pt, where x i = the result of the individual participant x pt = the reference value (the assigned value) s pt = the standard deviation for proficiency assessment Assigned value The reference value s pt % The standard deviation for proficiency assessment (s pt ) at the 95 % confidence level s result The result reported by the participant (the mean value of the replicates) Md Median SD Standard deviation SD% Standard deviation, % n (stat) Number of results in statistical processing Summary on the s S satisfactory ( z ) Q questionable ( < z < ), positive error, the result deviates more than s pt from the assigned value q questionable ( < z < ), negative error, the result deviates more than s pt from the assigned value U unsatisfactory (z ), positive error, the result deviates more than s pt from the assigned value u unsatisfactory (z ), negative error, the result deviates more than s pt from the assigned value Robust analysis The items of data are sorted into increasing order, x, x, x i,,x p. Initial values for x * and s * are calculated as: x * = median of x i (i =,,...,p) s * =.8 median of x i x * (i =,,...,p) The mean x * and s * are updated as follows: Calculate =.5 s *. A new value is then calculated for each result x i (i =, p): { x *, if x i < x * x * i = { x * +, if x i > x * +, { x i otherwise The new values of x * and s * are calculated from: * * x xi / p s. ( x i x ) /( p ) The robust estimates x * and s * can be derived by an iterative calculation, i.e. by updating the values of x * and s * several times, until the process convergences []. Proftest SYKE MET /6

33 APPENDIX 7 (/5) APPENDIX 7: Results of each participant Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN As AM mg/kg FO TN Cd AM mg/kg FO TN Co AM TN Cr AM mg/kg FO TN Cu AM mg/kg FO TN Fe AM TN Mn AM TN Mo mg/kg FO Ni AM Pb AM mg/kg FO TN Zn AM mg/kg FO TN Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN As AM TN Cd AM TN Co AM TN Cr AM TN Cu AM TN Fe AM TN Proftest SYKE MET /6

34 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Mn AM TN Ni AM TN Pb AM TN Se AM TN V AM TN Zn AM TN Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cd AM mg/kg FO TN VM Co TN Cr mg/kg FO TN Cu AM mg/kg FO TN VM Fe AM TN Ni AM TN Pb AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Proftest SYKE MET /6

35 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN As AM TN Cd AM TN Co AM TN Cr AM TN Cu AM TN Fe AM TN Hg AHg THg Mn AM TN Ni AM TN Pb AM TN Se AM TN Zn AM TN Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FN TN VM Ba mg/kg FN Cd AM mg/kg FN TN VM Co AM TN VM Cr AM mg/kg FN TN VM Proftest SYKE MET /6

36 APPENDIX 7 (/5) 5 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cu AM mg/kg FN TN VM Fe AM TN VM Hg AHg mg/kg FC THg VHg Mn AM TN VM Mo mg/kg FN Ni AM TN VM Pb AM mg/kg FN TN VM Se AM TN VM V AM mg/kg FN TN VM Zn AM mg/kg FN TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cu TY 5 5, VM., Fe TY VM 6 5 6, Hg THg VHg Mn TY VM Zn TY 5 5, VM. 5, Proftest SYKE MET /6

37 APPENDIX 7 (5/5) 7 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN TY VM As AM mg/kg FN TN TY VM Ba mg/kg FN Cd AM mg/kg FN TN TY VM Co AM TN TY VM Cr AM mg/kg FN TN TY VM Cu AM mg/kg FN TN TY VM Fe AM TN TY VM Hg AHg mg/kg FN THg VHg Mn AM TN TY VM Mo mg/kg FN Ni AM TN TY VM Pb AM mg/kg FN Proftest SYKE MET /6 5

38 APPENDIX 7 (6/5) 7 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Pb TN TY VM Se AM TN TY VM V AM mg/kg FN TN TY VM Zn AM mg/kg FN TN TY VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM.. 7 As AM mg/kg FO TN VM Ba mg/kg FO Cd AM mg/kg FO TN VM Co AM TN VM Cr AM mg/kg FO TN VM Cu AM mg/kg FO TN VM Fe AM TN VM Hg AHg mg/kg FO Proftest SYKE MET /6

39 APPENDIX 7 (7/5) 8 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Hg THg VHg Mn AM TN VM Mo mg/kg FO Ni AM TN VM Pb AM mg/kg FO TN VM Se AM TN VM V AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM.9. 7 As AM TN VM Cd AM TN VM Co AM TN VM Cr AM TN VM Cu AM TN VM Fe AM TN VM Proftest SYKE MET /6 7

40 APPENDIX 7 (8/5) 9 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Hg AHg THg VHg Mn AM TN VM Ni AM TN VM Pb AM TN VM Se AM TN VM V AM TN VM Zn AM TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FO TN VM Ba mg/kg FO Cd AM mg/kg FO TN VM Co AM TN VM Cr AM mg/kg FO TN VM Cu AM mg/kg FO TN VM Fe AM Proftest SYKE MET /6

41 APPENDIX 7 (9/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Fe TN VM Hg AHg mg/kg FO THg VHg Mn AM TN VM Mo mg/kg FO Ni AM TN VM Pb AM mg/kg FO TN VM Se AM TN VM V AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TY VM.8. 7 As AM mg/kg FT TY VM Ba mg/kg FT Cd AM mg/kg FT TY VM Co AM TY VM Cr AM mg/kg FT Proftest SYKE MET /6 9

42 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cr TY VM Cu AM mg/kg FT TY VM Fe AM TY VM Hg AHg mg/kg FN THg VHg Mn AM TY VM Mo mg/kg FT Ni AM TY VM Pb AM mg/kg FT TY VM Se AM TY VM V AM mg/kg FT TY VM Zn AM mg/kg FT TY VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FN TN VM Ba mg/kg FN Cd AM mg/kg FN Proftest SYKE MET /6

43 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cd TN VM Co AM TN VM Cr AM mg/kg FN TN VM Cu AM mg/kg FN TN VM Fe AM TN VM Mn AM TN VM Mo mg/kg FN Ni AM TN VM Pb AM mg/kg FN TN VM Se AM TN VM V AM mg/kg FN TN VM Zn AM mg/kg FN TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FO TN VM Proftest SYKE MET /6

44 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Ba mg/kg FO Cd AM mg/kg FO TN VM Co AM TN VM Cr AM mg/kg FO TN VM Cu AM mg/kg FO TN VM Fe AM TN VM Hg AHg mg/kg FO THg VHg Mn AM TN VM Mo mg/kg FO Ni AM TN VM Pb AM mg/kg FO TN VM Se AM TN VM V AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Proftest SYKE MET /6

45 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM TN VM Cd AM TN VM Co AM TN VM Cr AM TN VM Cu AM TN VM Fe AM TN VM Hg AHg THg VHg Mn AM TN VM Ni AM TN VM Pb AM TN VM Se AM TN VM V AM TN VM Zn AM TN VM Proftest SYKE MET /6

46 APPENDIX 7 (/5) 5 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN TY VM.8. 7 As AM mg/kg FN mg/kg FO TN TY VM Cd AM mg/kg FN mg/kg FO TN TY VM Co AM TN TY VM Cr AM mg/kg FN mg/kg FO TN TY VM Cu AM mg/kg FN mg/kg FO TN TY VM Fe AM TN TY VM Hg AHg mg/kg FC THg VHg Mn AM TN TY VM Mo mg/kg FN mg/kg FO Ni AM TN Proftest SYKE MET /6

47 APPENDIX 7 (5/5) 5 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Ni TY VM Pb AM mg/kg FN mg/kg FO TN TY VM Se AM TN TY VM V AM mg/kg FN mg/kg FO TN TY VM Zn AM mg/kg FN mg/kg FO TN TY VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FN TN VM Ba mg/kg FN Cd AM mg/kg FN TN VM Co AM TN VM Cr AM mg/kg FN TN VM Cu AM mg/kg FN Proftest SYKE MET /6 5

48 APPENDIX 7 (6/5) 6 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cu TN VM Fe AM TN VM Hg AHg mg/kg FN THg VHg Mn AM TN VM Mo mg/kg FN Ni AM TN VM Pb AM mg/kg FN TN VM Se AM TN VM V AM mg/kg FN TN VM Zn AM mg/kg FN TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FO TN VM Ba mg/kg FO Cd AM mg/kg FO TN VM Co AM TN Proftest SYKE MET /6

49 APPENDIX 7 (7/5) 7 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Co VM Cr AM mg/kg FO TN VM Cu AM mg/kg FO TN VM Fe AM TN 5 < 5 7. VM Hg AHg mg/kg FO THg VHg Mn AM TN VM Mo mg/kg FO Ni AM TN VM Pb AM mg/kg FO TN VM Se AM TN VM V AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN TY VM.8. 7 As AM mg/kg FO TN Proftest SYKE MET /6 7

50 APPENDIX 7 (8/5) 8 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) As TY VM Ba mg/kg FO Cd AM mg/kg FO TN TY VM Co AM TN TY VM Cr AM mg/kg FO TN TY VM Cu AM mg/kg FO TN TY VM Fe AM TN TY VM Hg AHg mg/kg FO THg VHg Mn AM TN TY VM Mo mg/kg FO Ni AM TN TY VM Pb AM mg/kg FO TN TY VM Se AM TN TY VM Proftest SYKE MET /6

51 APPENDIX 7 (9/5) 8 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) V AM mg/kg FO TN TY VM Zn AM mg/kg FO TN TY VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM mg/kg FO TN VM Ba mg/kg FO Cd AM mg/kg FO TN VM Co AM TN VM Cr AM mg/kg FO TN VM Cu AM mg/kg FO TN VM Fe AM TN VM Hg AHg mg/kg FO. <, THg VHg Mn AM TN VM Mo mg/kg FO Ni AM Proftest SYKE MET /6 9

52 APPENDIX 7 (/5) 9 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Ni TN VM Pb AM mg/kg FO TN VM Se AM TN VM V AM mg/kg FO TN VM Zn AM mg/kg FO TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cd mg/kg FN Cu mg/kg FN TY Fe AM TN VM Pb mg/kg FN TY Zn AM mg/kg FN TY Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TY Co AM TY Cr AM TY Fe AM TY Zn AM TY Proftest SYKE MET /6

53 APPENDIX 7 (/5) Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM As AM TN VM Cd AM TN VM Co AM TN VM Cr AM TN VM Cu AM TN VM Fe AM TN VM Mn AM TN VM Ni AM TN VM Pb AM TN VM Zn AM TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cr AM TN Fe AM TN Ni AM TN Zn AM TN Proftest SYKE MET /6 5

54 APPENDIX 7 (/5) 5 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al VM As mg/kg FN mg/kg FT VM Ba mg/kg FN mg/kg FT 5 9. Cd mg/kg FN mg/kg FT VM Co VM Cr mg/kg FN mg/kg FT VM Cu mg/kg FN mg/kg FT VM Fe VM Hg mg/kg FC mg/kg FN VHg Mn VM Mo mg/kg FN mg/kg FT Ni VM Pb mg/kg FN mg/kg FT VM Se VM V mg/kg FN mg/kg FT VM Zn mg/kg FN mg/kg FT VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TY VM As AM mg/kg FO TY VM 8.58 < Ba mg/kg FO Cd AM mg/kg FO TY Proftest SYKE MET /6

55 APPENDIX 7 (/5) 6 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Cd VM Co AM TY VM Cr AM mg/kg FO TY VM Cu AM mg/kg FO TY VM Fe AM TY VM Hg AHg mg/kg FO. <, THg VHg Mn AM TY VM Mo mg/kg FO Ni AM TY VM Pb AM mg/kg FO TY VM.6 5 < Se AM TY VM V AM mg/kg FO TY VM Zn AM mg/kg FO TY VM Proftest SYKE MET /6 5

56 APPENDIX 7 (/5) 7 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TN VM Cr mg/kg FN Cu AM mg/kg FN TN VM Fe AM TN VM Mn AM TN VM Ni AM TN Zn AM mg/kg FN TN VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM TY VM As AM mg/kg FO TY VM Cd AM mg/kg FO TY VM Co AM TY VM Cr AM mg/kg FO TY VM Cu AM mg/kg FO TY VM Fe AM TY VM Proftest SYKE MET /6

57 APPENDIX 7 (5/5) 8 Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Hg AHg THg VHg Mn AM TY VM Ni AM TY VM Pb AM mg/kg FO TY VM Se AM TY VM V AM mg/kg FO TY VM Zn AM mg/kg FO TY VM Measurand Unit Sample Assigned value spt % 's result Md Mean SD SD% n (stat) Al AM Co AM Cr AM Fe AM Zn AM Proftest SYKE MET /6 55

58 APPENDIX 8 (/) APPENDIX 8: Summary of the s Measurand Sample % Al AM S S. S S. S S S S S S S S S S U S S. Q S.. S S S S 9. TN S S. S S. S S S S. S S S S S Q S S.. S... S.. 9. TY S... S... S.. S.. S... S. S. VM.... S. S S S S S S S S S S U S S.. U. S S S S As AM S S. S S. S S S S S S S S S S U S S.. S.. S. q. 9. FN FO S S. Q.. S. S. S S S..... S. S. 9. FT TN S Q. S S. S S S S. S S S S Q U S S.. S TY VM.... S. S S S S S S S S S S Q S S.. S. S.. S. 9. Ba FN FO FT Cd AM S S u S S. S S S S S S S S S S U S S.. S.. S. S. 9.5 FN.... Q. S.... S.. S S... S... S FO u. S.... S. S.. S. S. S S S..... S. S. 9.9 FT TN S S S S S. S S S S. S S S S S S S S.. S TY S... S... S.. S S. S. VM.. U. S. S S S S S S S S S S U S S.. S. S S. S Co AM S S. S S. S S S S S S S S S S S S S. S S.. S. q S 95.5 TN S S U S S. S S S S. S S S S S S S S.. S TY S... S... S.. S.. S... S. S. VM.... S. S S S S S S S S S S S S S.. S. S S. S. Cr AM S S. S S. S S S S S S S S S S S S S. S S S. S. S S FN.... u. S.... S.. S S S. S FO S. u.... Q. S.. S. S. S S S..... S. S. 8.8 FT TN S S u S S. S S S S. S S S S S S S S.. S S TY S... S... S.. S.. S... S. S. VM.... S. S S S S S S S S S S S S S.. S. S S. S. Cu AM S S u q S. S S S S S S S S S S S S S.. S.. S S q. 86. FN.... S. S.... S.. S S... S... S. S.. FO S. S.... S. S.. S. S. S S S..... S. S. FT TN S S U S S. S S S S. S S S S S S S S.. S... S TY S... S... S.. S. S.... S. S. VM.. S. S. S S S S S S S S S S S S S.. S. S S S S. Fe AM S S S S S. S S S S u S S S S S U S S S S S S. S S S S 9. TN S S S S S. S S S S. S S S S S. S S S. S S.. S.. TY S... S... S.. S.. S... S. S. VM.... S. S S S S S S S S S S S S S q. S. S S S S Proftest SYKE MET /6

59 APPENDIX 8 (/) Measurand Sample % Hg AHg... S u. S S S Q S. S S S S U S S..... q. S. 75. FC FN FO FT THg... q u S S S S S S. S S S S U S S..... S. Q VHg.... S S S S S S Q. S S S S U S S.... S S. S. 88. Mn AM S S. S S. S S S S u S S S S S S S S.. S.. S S S. 95. TN S S. S S. S S S S. S S S S S S S S.. S... S.. TY S... S... S.. S S. S. VM.... S. S S S S S S S S S S S S Q.. S. S S S S. 9.7 Mo FN.... Q. S.... S.. S S S FO S S. S.. S. S. S S S..... S... FT Ni AM S S S S S. S S S S S S S S S S S S S.. S S. S S q TN. S Q S S. S S S S. S S S S S S S S.. S S.. S TY S... S... S.. S S. S. VM.... S. S S S S S S S q S S S S S.. S. S S. S. 9. Pb AM Q S u S S. S S S S S S S S S S S S S.. S.. S. S. 9.5 FN.... S. S.... S.. S S... S... S.... FO q. S.... S. S.. S. S. S S S..... S. S. 9.9 FT TN S S U S S. S S S S. q S q S S S S S.. S TY S... S... S.. S. S.... S. Q VM.. U. S. S S S S S S S U S S S S S.. S. S.. S Se AM. S. S S. S S S S S S S S S S U S S..... S. q TN. S. S S. S S S S. S S S S Q U Q S TY S... S... S.. u S. S. 8. VM.... S. S S S S S S S U S S U S S.... S U. S. 8. V AM. S.. S. S S S S S S S S S S S S S..... S. S. FN.... S. S.... S.. S S S.... FO S. S.. S. S. S S S..... S. S. FT TN. S.. S. S S S q. S S S S S Q S S TY S... S... S.. S S. S. VM.... S. S S S S S S S S S S S S Q.... S S. S. 9. Zn AM S S S Q S. S S S S S S S S S S U S S q S S S. S S S q 8.6 FN.... S. S.... S.. S S... u... S. S FO u. u.... S. S.. S. S. S q S..... S. S. 7.7 FT TN S S S S S. S S S S. S S S S S U u S.. S S.. S.. 9. TY S... S... S.. u. S u... S. S. 75. VM.. S. S. S S S S S S S S S S U S S.. S. S S S S. 95. % accredited S satisfactory ( < z < ), Q questionable ( < z < ), q questionable ( < z < ), U unsatisfactory (z > ), and u unsatisfactory (z < ), respectively bold accredited, italics nonaccredited, normal other % percentage of satisfactory results Totally satisfactory, % in all: 9 % in accredited: 96 % in nonaccredited: 86 Proftest SYKE MET /6 57

60 APPENDIX 9 (/) APPENDIX 9: s in ascending order Measurand Al Sample AM Measurand Al Sample TN Measurand Al Sample TY Proftest SYKE MET /6

61 APPENDIX 9 (/) Measurand Al Sample VM Measurand As Sample AM Measurand As Sample FO Proftest SYKE MET /6 59

62 APPENDIX 9 (/) Measurand As Sample TN Measurand As Sample VM Measurand Cd Sample AM Proftest SYKE MET /6

63 APPENDIX 9 (/) Measurand Cd Sample FN Measurand Cd Sample FO Measurand Cd Sample TN Proftest SYKE MET /6 6

64 APPENDIX 9 (5/) Measurand Cd Sample TY Measurand Cd Sample VM Measurand Co Sample AM Proftest SYKE MET /6

65 APPENDIX 9 (6/) Measurand Co Sample TN Measurand Co Sample TY Measurand Co Sample VM Proftest SYKE MET /6 6

66 APPENDIX 9 (7/) Measurand Cr Sample AM Measurand Cr Sample FN Measurand Cr Sample FO Proftest SYKE MET /6

67 APPENDIX 9 (8/) Measurand Cr Sample TN Measurand Cr Sample TY Measurand Cr Sample VM Proftest SYKE MET /6 65

68 APPENDIX 9 (9/) Measurand Cu Sample AM Measurand Cu Sample FN Measurand Cu Sample FO Proftest SYKE MET /6

69 APPENDIX 9 (/) Measurand Cu Sample TN Measurand Cu Sample TY Measurand Cu Sample VM Proftest SYKE MET /6 67

70 APPENDIX 9 (/) Measurand Fe Sample AM Measurand Fe Sample TN Measurand Fe Sample TY Proftest SYKE MET /6

71 APPENDIX 9 (/) Measurand Fe Sample VM Measurand Hg Sample AHg Measurand Hg Sample THg Proftest SYKE MET /6 69

72 APPENDIX 9 (/) Measurand Hg Sample VHg Measurand Mn Sample AM Measurand Mn Sample TN Proftest SYKE MET /6

73 APPENDIX 9 (/) Measurand Mn Sample TY Measurand Mn Sample VM Measurand Mo Sample FN Proftest SYKE MET /6 7

74 APPENDIX 9 (5/) Measurand Mo Sample FO Measurand Ni Sample AM Measurand Ni Sample TN Proftest SYKE MET /6

75 APPENDIX 9 (6/) Measurand Ni Sample TY Measurand Ni Sample VM Measurand Pb Sample AM Proftest SYKE MET /6 7

76 APPENDIX 9 (7/) Measurand Pb Sample FN Measurand Pb Sample FO Measurand Pb Sample TN Proftest SYKE MET /6

77 APPENDIX 9 (8/) Measurand Pb Sample TY Measurand Pb Sample VM Measurand Se Sample AM Proftest SYKE MET /6 75

78 APPENDIX 9 (9/) Measurand Se Sample TN Measurand Se Sample TY Measurand Se Sample VM Proftest SYKE MET /6

79 APPENDIX 9 (/) Measurand V Sample AM Measurand V Sample FN Measurand V Sample FO Proftest SYKE MET /6 77

80 APPENDIX 9 (/) Measurand V Sample TN Measurand V Sample TY Measurand V Sample VM Proftest SYKE MET /6

81 APPENDIX 9 (/) Measurand Zn Sample AM Measurand Zn Sample FN Measurand Zn Sample FO Proftest SYKE MET /6 79

82 APPENDIX 9 (/) Measurand Zn Sample TN Measurand Zn Sample TY Measurand Zn Sample VM Proftest SYKE MET /6

83 APPENDIX (/) APPENDIX : Summary of D% and E n scores D% scores Measurand Sample As FN FT TY Ba FN FO FT Cd FT Cr FT Hg FC FN FO Mo FT Pb FT V FT Zn FT D can be interpreted as the measurement error for the result, to the extent to which assigned value can be considered a reference quantity value E n scores Measurand Sample % As FN TY E n scores enable to estimate the proximity of participant results to the assigned value taking into consideration their reported expanded uncertainty Scores of. < E n <. indicate successful performance Scores of E n >. or E n <. indicate a need to review the uncertainty estimated or to correct a measurement issue Proftest SYKE MET /6 8

84 APPENDIX (/9) APPENDIX : Results grouped according to the methods In figures: The dashed lines describe the standard deviation for the proficiency assessment, the red solid line shows the assigned value, the shaded area describes the expanded measurement uncertainty of the assigned value, and the arrow describes the value outside the scale. Measurand Al Sample AM ICPOES ICPMS Measurand Al Sample TN ICPOES ICPMS Measurand Al Sample TY ICPOES ICPMS 8 Proftest SYKE MET /6

85 APPENDIX (/9) Measurand Al Sample VM ICPOES ICPMS Measurand As Sample AM GAAS ICPOES ICPMS Measurand As Sample FN, 9,5 9, mg/kg 8,5 8, 7,5 7, 5 ICPOES ICPMS Proftest SYKE MET /6 8

86 APPENDIX (/9) Measurand As Sample FO mg/kg ICPOES ICPMS Measurand As Sample FT 9, 8,5 mg/kg 8, 7,5 7, 5 ICPMS Measurand As Sample TN GAAS ICPOES ICPMS 8 Proftest SYKE MET /6

87 APPENDIX (/9) Measurand As Sample TY ICPOES ICPMS Measurand As Sample VM,6,8, 9, 8, 7,6 6,8 6, 5, 5 5 ICPOES ICPMS Measurand Ba Sample FN 5 mg/kg ICPOES ICPMS Proftest SYKE MET /6 85

88 APPENDIX (5/9) Measurand Ba Sample FO 79 mg/kg ICPOES ICPMS Measurand Ba Sample FT mg/kg ICPOES ICPMS Measurand Cd Sample AM 9, 8,7 8, 7,9 7,5 7, 6,7 6, 5,9 5,5 5, 5 5 GAAS ICPOES ICPMS Other method 86 Proftest SYKE MET /6

89 APPENDIX (6/9) Measurand Cd Sample FN 8 6 mg/kg ICPOES ICPMS Other method Measurand Cd Sample FO 6 mg/kg FAAS ICPOES ICPMS Measurand Cd Sample FT,,5 mg/kg, 9,5 9, 5 ICPMS Proftest SYKE MET /6 87

90 APPENDIX (7/9) Measurand Cd Sample TN FAAS GAAS ICPOES ICPMS Measurand Cd Sample TY ICPOES ICPMS Measurand Cd Sample VM 5,5 5,,7,,9,5, 5 5 ICPOES ICPMS Other method 88 Proftest SYKE MET /6

91 APPENDIX (8/9) Measurand Co Sample AM GAAS ICPOES ICPMS Measurand Co Sample TN FAAS GAAS ICPOES ICPMS Measurand Co Sample TY ICPOES ICPMS Proftest SYKE MET /6 89

92 APPENDIX (9/9) Measurand Co Sample VM ICPOES ICPMS Measurand Cr Sample AM GAAS ICPOES ICPMS Measurand Cr Sample FN 5 mg/kg ICPOES ICPMS 9 Proftest SYKE MET /6

93 APPENDIX (/9) Measurand Cr Sample FO mg/kg FAAS ICPOES ICPMS Measurand Cr Sample FT 6 5 mg/kg 5 ICPMS Measurand Cr Sample TN FAAS GAAS ICPOES ICPMS Proftest SYKE MET /6 9

94 APPENDIX (/9) Measurand Cr Sample TY ICPOES ICPMS Measurand Cr Sample VM ICPOES ICPMS Measurand Cu Sample AM GAAS ICPOES ICPMS Other method 9 Proftest SYKE MET /6

95 APPENDIX (/9) Measurand Cu Sample FN mg/kg ICPOES ICPMS Other method Measurand Cu Sample FO mg/kg FAAS ICPOES ICPMS Measurand Cu Sample FT 5 mg/kg ICPOES ICPMS Proftest SYKE MET /6 9

96 APPENDIX (/9) Measurand Cu Sample TN FAAS GAAS ICPOES ICPMS Measurand Cu Sample TY ICPOES ICPMS Other method Measurand Cu Sample VM ICPOES ICPMS Other method 9 Proftest SYKE MET /6

97 APPENDIX (/9) Measurand Fe Sample AM FAAS ICPOES ICPMS Other method Measurand Fe Sample TN FAAS ICPOES ICPMS Other method Measurand Fe Sample TY ICPOES ICPMS Proftest SYKE MET /6 95

98 APPENDIX (5/9) Measurand Fe Sample VM ICPOES ICPMS Other method Measurand Hg Sample AHg,8,7,6,5, 5 5 CVAAS CVAFS CVICPMS Direct combustion (O flow + AAS) ICPMS Other method Measurand Hg Sample FC,,9 mg/kg,8,7,6 5 CVAAS CVICPMS Direct combustion (O flow + AAS) 96 Proftest SYKE MET /6

99 APPENDIX (6/9) Measurand Hg Sample FN,,5, mg/kg,95,9,85,8 5 CVAFS ICPMS Other method Measurand Hg Sample FO,,5 mg/kg,,5, 5 CVAAS ICPOES ICPMS Other method Measurand Hg Sample FT Proftest SYKE MET /6 97

100 APPENDIX (7/9) Measurand Hg Sample THg,,9,5,,7,,9 5 5 CVAAS CVAFS CVICPMS Direct combustion (O flow + AAS) ICPMS Other method Measurand Hg Sample VHg 7, 6,8 6, 6, 5,6 5,,8,,,6, 5 5 CVAAS CVAFS CVICPMS Direct combustion (O flow + AAS) ICPMS Other method Measurand Mn Sample AM ICPOES ICPMS 98 Proftest SYKE MET /6

101 APPENDIX (8/9) Measurand Mn Sample TN ICPOES ICPMS Measurand Mn Sample TY ICPOES ICPMS Measurand Mn Sample VM ICPOES ICPMS Proftest SYKE MET /6 99

102 APPENDIX (9/9) Measurand Mo Sample FN 5 mg/kg ICPOES ICPMS Measurand Mo Sample FO 8 mg/kg ICPOES ICPMS Measurand Mo Sample FT,,5, mg/kg,5, 9,5 9, 5 ICPOES ICPMS Proftest SYKE MET /6

103 APPENDIX (/9) Measurand Ni Sample AM FAAS GAAS ICPOES ICPMS Measurand Ni Sample TN FAAS GAAS ICPOES ICPMS Measurand Ni Sample TY ICPOES ICPMS Proftest SYKE MET /6

104 APPENDIX (/9) Measurand Ni Sample VM,5,7 9,9 9, 8, 7,5 6,7 5,9 5, 5 5 ICPOES ICPMS Measurand Pb Sample AM GAAS ICPOES ICPMS Other method Measurand Pb Sample FN 9 7 mg/kg ICPOES ICPMS Other method Proftest SYKE MET /6

105 APPENDIX (/9) Measurand Pb Sample FO mg/kg FAAS ICPOES ICPMS Measurand Pb Sample FT 8, 77,5 mg/kg 75, 7,5 7, 5 ICPMS Measurand Pb Sample TN FAAS GAAS ICPOES ICPMS Proftest SYKE MET /6

106 APPENDIX (/9) Measurand Pb Sample TY ICPOES ICPMS Other method Measurand Pb 5,7 Sample VM 5,,9,5,,7, 5 5 ICPOES ICPMS Other method Measurand Se Sample AM GAAS ICPOES ICPMS Proftest SYKE MET /6

107 APPENDIX (/9) Measurand Se Sample TN GAAS ICPOES ICPMS Measurand Se Sample TY ICPOES ICPMS Measurand Se Sample VM 9,8 9, 9, 8,6 8, 7,8 7, 7, 6,6 6, 5,8 5, 5 5 ICPOES ICPMS Proftest SYKE MET /6 5

108 APPENDIX (5/9) Measurand V Sample AM GAAS ICPOES ICPMS Measurand V Sample FN 6 98 mg/kg ICPOES ICPMS Measurand V Sample FO mg/kg ICPOES ICPMS 6 Proftest SYKE MET /6

109 APPENDIX (6/9) Measurand V Sample FT mg/kg ICPMS Measurand V Sample TN GAAS ICPOES ICPMS Measurand V Sample TY ICPOES ICPMS Proftest SYKE MET /6 7

110 APPENDIX (7/9) Measurand V Sample VM ICPOES ICPMS Measurand Zn Sample AM FAAS ICPOES ICPMS Other method Measurand Zn Sample FN mg/kg ICPOES ICPMS Other method 8 Proftest SYKE MET /6

111 APPENDIX (8/9) Measurand Zn Sample FO mg/kg FAAS ICPOES ICPMS Measurand Zn Sample FT mg/kg ICPOES ICPMS Measurand Zn Sample TN FAAS ICPOES ICPMS Proftest SYKE MET /6 9

112 APPENDIX (9/9) Measurand Zn Sample TY ICPOES ICPMS Other method Measurand Zn Sample VM ICPOES ICPMS Other method Proftest SYKE MET /6

113 APPENDIX (/) APPENDIX : Significant differences in the results reported using different methods Boxplot figures: In the box the upper and lower limit included 5 % of the results. The dashed vertical line in the middle of the box is the median of the results. The vertical lines above and under the box describe the limits of 8 % of the results. The black dots describe the highest and smallest results within the center 9 % of the results. Statistically significant differences between different acid digestions (fly ash) Measurand Cr Sample FN 9 8 FO FN Method n Mean (mg/kg) SD (mg/kg) FN: digestion with HNO FO: digestion with HNO+HCl 96 FT: digestion with HNO+HF 9 n = number of results; SD = standard deviation Statistically significant differences between analytical methods Measurand Al Sample VM 9 Method 6 Method 6 Method n Mean () SD () Method 6: ICPOES 8 Method 6: ICPMS n = number of results; SD = standard deviation Proftest SYKE MET /6

114 APPENDIX (/) Measurand Mn Sample AM Method 6 Method 6 Method n Mean () SD () Method 6: ICPOES 58 5 Method 6: ICPMS 6 6 n = number of results; SD = standard deviation Measurand Ni Sample AM Method 6 Method 6 Method n Mean () SD () Method 6: ICPOES Method 6: ICPMS n = number of results; SD = standard deviation Proftest SYKE MET /6

115 APPENDIX (/9) APPENDIX : Estimation of the measurement uncertainties reported by the participants In figures, the presented expanded measurement uncertainties are grouped according to the method of estimation at 95 % confidence level (k=). The expanded uncertainties were estimated mainly by using the internal quality control (IQC) data. The used procedures in figures below are distinguished e.g. between using or not using the MUkit software for uncertainty estimation [8, 9] or using a modelling approach based [, ]. Measurand Al Uncertainty, Ui % Sample AM IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Al Uncertainty, Ui % Sample TN IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand As Uncertainty, Ui % Sample FO IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6

116 APPENDIX (/9) Measurand As Sample TN Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Ba Sample FO 5 Uncertainty, Ui % 5 5 IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Measurand Cd Sample AM Uncertainty, Ui % 6 5 IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6

117 APPENDIX (/9) Measurand Cd Sample FO Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Measurand Cd Sample VM Uncertainty, Ui % 6 5 IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Co Sample AM Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6 5

118 APPENDIX (/9) Measurand Cr Uncertainty, Ui % Sample FN IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Cr Sample TN Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Cu Uncertainty, Ui % Sample FO IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. 6 Proftest SYKE MET /6

119 APPENDIX (5/9) Measurand Fe Uncertainty, Ui % Sample VM IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Hg Uncertainty, Ui % 5 Sample AHg IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Hg 6 Sample FO 5 Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6 7

120 APPENDIX (6/9) Measurand Hg Uncertainty, Ui % 5 Sample THg IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Mn Uncertainty, Ui % Sample TN IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Mo Uncertainty, Ui % Sample FO IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. 8 Proftest SYKE MET /6

121 APPENDIX (7/9) Measurand Ni Sample AM Uncertainty, Ui % IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Pb Uncertainty, Ui % Sample AM IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Pb Sample FO Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6 9

122 APPENDIX (8/9) Measurand Se Sample VM Uncertainty, Ui % 6 5 IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand V Sample AM Uncertainty, Ui % IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand V Sample FO Uncertainty, Ui % 6 5 IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6

123 APPENDIX (9/9) Measurand Zn Uncertainty, Ui % Sample FN IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Measurand Zn Uncertainty, Ui % Sample VM IQC data only from synthetic control sample and/or CRM (X chart), no MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), MUkit software. IQC data from both synthetic sample (Xchart) and routine sample replicates (R or r%chart), no MUkit software. IQC data and the results obtained in proficiency tests, no MUkit software. Data obtained from method validation, with MUkit software. Data obtained from method validation, no MUkit software. Proftest SYKE MET /6

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