Proficiency Test SYKE 8a/2010

Transkriptio

1 REPORTS OF FINNISH ENVIRONMENT INSTITUTE 0 Proficiency Test SYKE a/0 Volatile organic compounds in water and soil Kaija Korhonen-Ylönen, Jari Nuutinen, Mirja Leivuori and Markku Ilmakunnas Finnish Environment Institute

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3 REPORTS OF FINNISH ENVIRONMENT INSTITUTE 0 Proficiency Test SYKE a/0 Volatile organic compounds in water and soil Kaija Korhonen-Ylönen, Jari Nuutinen, Mirja Leivuori and Markku Ilmakunnas Helsinki 0 Finnish Environment Institute

4 REPORTS OF FINNISH ENVIRONMENT INSTITUTE 0 Finnish Environment Institute SYKE The organizer of the intercomparison test: Finnish Environment Institute SYKE, Laboratories Hakuninmaantie, 000 Helsinki phone + 0, fax + Publication is available only in the internet : ISBN ---- (PDF) ISSN - (online)

5 CONTENT PREFACE/ALKUSANAT INTRODUCTION ORGANIZING OF THE POFICIENCY TEST. Responsibilities. Participants. Samples and their delivery. Homogeneity and stability studies. Feedback from the pro ciency test. Prosessing of the data.. Testing of outliers and normality of the data.. Assigned value.. Standard deviation for pro ciency assessment and z score RESULTS AND CONCLUSIONS. Results. Analytical methods. Uncertainties of the results EVALUATION OF PERFORMANCE SUMMARY YHTEENVETO REFERENCES APPENDIXES Participants in the PT SYKE a / 0 Preparation of the samples Testing of homogeneity Testing of stability. Feedback from the participants 0. Feedback to the participants Assigned values and their uncertainties Results of each laboratory The results and their uncertainties graphically Explanations for the result sheets. Analytical methods 0. Results grouped according to the methods Examples of the reported measurement uncertainties grouped according to the evaluation procedure Summary of the z-scores DOCUMENTATION PAGE KUVAILULEHTI 0 PRESENTATIONBLAD

6 ALKUSANAT Suomen ympäristökeskus (SYKE) on toiminut ympäristöalan kansallisena vertailulaboratoriona vuodesta 00 lähtien. Toiminta perustuu ympäristöministeriön määräykseen, mikä on annettu ympäristönsuojelulain (/000) nojalla. Vertailulaboratorion tarjoamista palveluista yksi tärkeimmistä on pätevyyskokeiden ja muiden vertailumittausten järjestäminen. SYKEn laboratoriot on FINAS-akkreditointipalvelun akkreditoima testauslaboratorio T00 (EN ISO/IEC 0) ja vertailumittausten järjestäjä Proftest SYKE PT0 (EN ISO/IEC 0, www. nas. ). Tämä pätevyyskoe on toteutettu Proftest SYKEn pätevyysalueella ja se antaa tietoa osallistujien pätevyyden lisäksi tulosten vertailukelpoisuudesta myös yleisemmällä tasolla. Pätevyyskokeen onnistumisen edellytys on järjestäjän ja osallistujien välinen luottamuksellinen yhteistyö. Parhaat kiitokset yhteistyöstä kaikille osallistujille! PREFACE Finnish Environment Institute (SYKE) has served as the National Reference in the environmental sector designated by the Ministry of the Environment under the section of the Environment Protection Act (/000) since 00. The duties of the reference laboratory service include providing pro ciency tests and other interlaboratory comparisons for analytical laboratories and other producers of environmental information. The SYKE laboratories has been accredited by the Finnish Accreditation service as the testing laboratory T00 (EN ISO/IEC 0) and as the pro ciency testing provider Proftest SYKE PT0 (EN ISO/IEC 0, www. nas. ). This pro ciency test has been carried out under the scope of the Proftest SYKE and it provides information about performance of the participants as well as comparability of the results at more general level. The success of the pro ciency test requires con dential co-operation between the provider and participants. Thank you for your co-operation! Helsingissä. helmikuuta 0 / Helsinki February 0 Laboratorionjohtaja / Chief of

7 INTRODUCTION In November 0 the Finnish Environment Institute (SYKE) carried out the pro ciency test (PT) for the analysis of volatile organic compounds (VOC) in water and soil. The test was carried out in accordance with the international standards, ISO/IEC 0 [] and ISO [] as well as IUPAC Recommendations []. The SYKE laboratory has been accredited by the Finnish Accreditation Service as a pro ciency testing provider Proftest SYKE PT0 (www. nas. ) on the eld of the present PT. ORGANIZING OF THE PROFICIENCY TEST. Responsibilities Organizing laboratory: Finnish Environment Institute (SYKE), Laboratories, Proftest SYKE Hakuninmaantie, 000 Helsinki, Finland Phone: + 0 Fax: + 0 The responsibilities in organizing the PT were as follows: Kaija Korhonen-Ylönen, coordinator Jari Nuutinen, analytical expert and coordinator trainee Mirja Leivuori, substitute of coordinator Helena Tanttu, technical assistant Markku Ilmakunnas, technical assistant, layout of the report Keijo Tervonen, technical assistant Sari Lanteeri, technical assistant. Participants In total, laboratories (Appendix ) from Denmark, Finland, Italy and Sweden participated in this PT. Eight laboratories used an accredited method at least for some of VOC compounds. The organizing laboratory (SYKE) had the code in the result tables.. Samples and their delivery The arti cial sample as well as the addition standard solution for the water sample and the soil sample was prepared gravimetrically from individual compounds by diluting to the nal concentration (Appendix ). Both the soil sample and the ground water sample were spiked with a known amount of the addition solution. The preparation of the samples is presented in Appendix. The samples were delivered November 0. They were requested to be analysed and reported at the latest November 0.. Homogeneity and stability studies Homogeneities of the sample and the sample were tested by analysing tetrachloroethene,,,-trichlorobenzene, o-xylene and MTBE as triplicate determinations from seven sub samples (Appendix ). Both samples were considered to be homogenous.

8 The stabilities of the samples and were checked during the sample transport to the participants. The sample vials were weighed at SYKE before the delivering and reweighed at the participating laboratory after the receiving. The differences of these two measurements should be < 0. %. During the transport no evaporation of solvent was observed. The stability test was carried out for all samples, and. One part of the samples was stored at the room temperature and the other part at the temperature C degrees over night. The samples were analysed 0 November (Appendix ). According to the test the increased temperature did not cause signi cant change in the samples and. The test results of the sample were slightly inconsistent. Only one laboratory reported the temperature of the samples to be higher than C. However, the results of this participant for the sample were satisfactory (z < ).. Feedback from the pro ciency test Appendix. contains the comments sent by the participants. The weight of the groundwater sample was asked to report unnecessarily because the initial weight was not given and evaporation of water during the transport was not probable. Consequently Appendix. contains the provider s comments to the participants. Only one participant sent the results a day after the deadline. However the results could be included in the preliminary data treatment. After sending the preliminary results the coordinator informed the participants that due to low number of the participants both unit errors and the results, which had been entered on inappropriate line, would be corrected by Proftest. No participant reported this kind of errors. As well according to the provider's observation the participants reported their results correctly in this PT. Only method descriptions of two participants were lacking.. Processing of the data.. Testing of outliers and normality of data Before the statistical treatment, the data was tested according to the Kolmogorov-Smirnov normality test and the possible extreme values were rejected as the outliers according to the Hampel test. Also before the robust calculation some outliers were rejected in case that the results deviated from the robust mean over 0 %... Assigned value The assigned values and their uncertainties are presented in Appendix. The calculated concentrations were used as the assigned values for the concentrations of all measurements in the arti cial sample. The uncertainty of the assigned value given is the expanded combined uncertainty based on the combination of uncertainties associated with individual operations involved in the preparation of the sample. In all cases the uncertainty was less than % and the main individual resource of the uncertainty was the uncertainty of the impurity in the stock solution. The robust means of the reported results were used as the assigned value for the concentrations of the measurements in both the water and the soil samples. The uncertainty of the assigned value was calculated using the robust standard deviation of the reported results as follows:

9 . srob 0 n U% AV where: U% = the expanded uncertainty of the assigned value AV = the assigned value s rob = the robust standard deviation n = the number of the results In the samples and the uncertainties of the assigned values varied from. % to %. After reporting of the preliminary results no signi cant correction of the assigned value has been done... Standard deviation for pro ciency assessment and z score The evaluation of the participants was based on z scores, which were calculated using the estimated standard deviation for pro ciency assessment. The estimation of the target standard deviation was based on the type of sample, the concentration of the analyte in the sample, the results of homogeneity and stability tests and the uncertainty of the assigned value. In the performance evaluation z scores were interpreted as follows: z satisfactory results < z < questionable results z unsatisfactory results The reliability of the assigned value was tested according the criterion u / s p 0., where u is the standard uncertainty (U / ) of the assigned value and s p the standard deviation for pro ciency assesment (target value for total deviation / ). Due to low number of the participants the criterion was not ful lled in every case, which indicated that the following assigned values had high uncertainty: : TCBz, DCEa, CCl, DCM, ETBz, mpxyl, MTBE, TAME, TeCEe : TCBz, DCEa, DCM, mpxyl, oxyl, TAME However, the ratios u / s p were in every case < 0.. The reliability of the target value for total deviation and correspondingly the z score were estimated by comparing the target value (s p ) with the robust standard deviation of the reported results (s rob ). Due to low number of the results the criterion s rob <. s p was not ful lled in most cases, which weakened the evaluation of performance. RESULTS AND CONCLUSIONS. Results The results and the performance of each laboratory are presented in Appendix and the summary of the results in Table. The results and their uncertainties are presented graphically in Appendix. Explanations for the result sheets are presented in Appendix.

10 Table. Summary of the pro ciency test a/0. where Ass. val. the assigned value Mean the mean value Mean rob the robust mean Md the median value SD % the standard deviation as percent SD rob the robust standard deviation SD rob % the robust standard deviation as percents Num of Labs the number of the participants *Targ. SD% the target value for total deviation at the % con dence interval (= s p ) Accepted z-val% the satisfactory z values: the results (%), where z. The robust deviations in the results of aromatic compounds varied from % to % and in the results of chlorinated compounds from. % to. %. Consequently the robust deviations of the results of oxygenates were between and %. The high deviation of the TAME and m/p xylene results from the synthetic sample indicated possible calibration problems.

11 . Analytical methods The analytical methods used by the participants are presented in Appendix.. VOC compounds in water VOC compounds were determined using the methods which were based on several ISO standards [ ]. All participants used either headspace or purge&trap -technique, but liquid-liquid extraction was not used. Most participants used GC-MS technique and only one participant (lab ) GC-FID technique. With the GC-MS technique at least toluene-d was used as internal standard. VOC compounds in soil Determination of VOC compounds from soil samples were also based on several standard methods or EPAs methods [ ]. Extraction was mostly done by shaking and only one participant heated the sample in headspace vial. Most participants used headspace as injection technique and three participants used purge&trap technique and only one split-technique. Equipment technique was mostly GC-MS and only one participant (lab ) used GC-FID. Statistical comparison between GC-MS and GC-FID was not possible, but according to the graphical presentation (Appendix ) the results of the lab (GC-FID) did not deviate from the other results. Method comparison was done between injection techniques and before method comparison the results were coded by coordinator as follows: - Method : Headspace - Method : Purge & Trap - Method : Split - Method : Unspeci ed method No signi cant difference could be obtained between the methods. According to the graphical presentation the unsatisfactory results were not due to the applied technique (Appendix.).. Uncertainties of the results Most laboratories ( %) reported the expanded uncertainties with their results (Appendix ). The reported uncertainties varied largely especially in the analysis of water samples (Table ). Most laboratories estimated uncertainties using the data of validation and internal quality control (Meth ). Reported evaluation procedures of the uncertainities did not explain the high variation between uncertainties between the laboratories (Appendix ). It is evident that harmonization in the estimation of uncertainties should be done. Table. The ranges of the reported expanded uncertainties in the analysis of water and soil samples

12 EVALUATION OF PERFORMANCE The evaluation of the participants was based on z scores, which were calculated using the estimated standard deviation for pro ciency assessment. The calculated z scores are presented with the results of each participant (Appendix ) and the summary of z scores is presented in Appendix. When accepting deviations of % from the assigned values for arti cial sample, % of the results of the aromatic hydrocarbons, % of the results of the chlorinated hydrocarbons and % the oxygenate results (MTBE and TAME) were satisfactory. In this PT the number of satisfactory results was at the same level as in the previous PT /00 []. Consequently, when accepting deviations of % from the assigned value in the determination of ground water sample, 0 % of the results of the aromatic compounds, % of the results of the chlorinated hydrocarbons and % of the oxygenate results were satisfactory. In this PT the number of the satisfactory results was slightly higher than in the previous PT /00 [], where on an average % of the results of the aromatic compounds were satisfactory. When accepting deviations of 0 % from the assigned values for the soil sample, % of the results of the aromatic hydrocarbons, % of the results of the chlorinated hydrocarbons and 0 % of the oxygenate results were satisfactory. The number of the satisfactory results in this PT was remarkable higher than in the previous PT /00 [], where on an average % of the results were satisfactory. In total, % of the total result data in this PT were satisfactory. More than the half of the participants used accredited methods. There was not any difference in performance between the accredited and not accredited determinations (Appendix ). For the priority substances (Table ) mentioned in the European Union ground water directive (00//EC) the amount of the accepted z-values of the participants results for sample were from % to 0 % (Table ). Environmental quality standard values (EQS) for the ground waters in the directive are higher than the assigned value in this pro ciency test for cdcee, CHCl, DCM, oxyl, TAME and TOL, and lower than the assigned value for TCBz, DCEa, Bz, CCl, ETBz, mpxyl, MTBE, TCEe and TECEe. The limit of quantitation for the priority substances should be / of the EQS values. Table The environmental quality standard (EQS) values for the compounds in ground waters = sum of compounds

13 SUMMARY Proftest SYKE carried out the pro ciency test for the determinations of volatile organic compounds (VOC) in water and soil samples in November 0. In total, laboratories participated in the pro ciency test. One arti cial sample (), one ground water sample () and one soil sample () were delivered to the laboratories. The calculated concentrations (sample ) or the robust mean of the results reported by the participants (samples and ) were used as the assigned values for measurands. The uncertainties of the calculated assigned values were less than %. Respectively the uncertainties of the consensus assigned values (the robust mean) were from. % to %. In total, % of the total result data in this PT were satisfactory when the deviations of 0 % from the assigned values were accepted. YHTEENVETO Proftest SYKE järjesti pätevyyskokeen haihtuvien orgaanisten yhdisteiden määrityksistä vesija maanäytteistä marraskuussa 0. Vesi- ja maanäytteiden lisäksi osallistujille toimitettiin synteettinen näyte. Pätevyyskokeeseen osallistui yhteensä laboratoriota. Synteettisessä näytteessä () mittaussuureen vertailuarvona käytettiin laskennallista pitoisuutta (teoreettinen arvo) ja vesi- ja maanäytteissä ( ja ) osallistujien raportoimien tulosten keskiarvoa (sopimusarvo). VOC-yhdisteiden laskennallisten vertailuarvojen laajennetut epävarmuudet olivat alle %. Yhdisteestä ja raportoitujen tulosten hajonnasta riippuen vertailuarvon laajennettu epävarmuus. %, kun vertailuarvona käytettiin sopimusarvoa. Synteettisten näytteiden tuloksissa sallittiin %:n poikkeama vertailuarvosta, jolloin aromaattisten yhdisteiden tuloksista hyväksyttäviä oli %, öljyn lisäaineiden tuloksista (MTBE ja TAME) % ja kloorattujen hiilivetyjen tuloksista %. Vuoden 00 vastaavassa vertailussa hyväksyttävien tulosten määrä oli samaa tasoa. Vesinäytteiden tuloksissa sallittiin %:n poikkeama vertailuarvosta, jolloin aromaattisten yhdisteiden tuloksista oli hyväksyttäviä 0 %, öljyn lisäainetuloksista % ja kloorattujen hiilivetyjen tuloksista %. Vuoden 00 vastaavassa vertailussa aromaattisten yhdisteiden tuloksista oli hyväksyttäviä 0 %, öljyn lisäaineiden tuloksista % ja kloorattujen hiilivetyjen tuloksista %. Maanäytteen tulosten sallittiin poiketa vertailuarvosta 0 %, jolloin aromaattisten hiilivetyjen tuloksista oli hyväksyttäviä %, öljyn lisäaineiden tuloksista 0 % ja kloorattujen hiilivetyjen tuloksia %. Vuoden 00 vastaavassa vertailussa sekä aromaattisten yhdisteiden että kloorattujen hiilivetyjen tuloksista oli hyväksyttäviä % ja öljyn lisäaineiden tuloksista 0 %. Euroopan unionin pohjavesidirektiivissä (00//EY, valtioneuvoston asetus /00) prioriteetti aineiden (Table ) z-arvoista näytteessä 0 % oli hyväksyttyjä (Table ). Pohjavesidirektiivin yhdisteiden ympäristölaatunormit (EQS) ovat korkeammat kuin tässä pätevyyskokeessa tavoitearvot seuraaville yhdisteille; cdcee, CHCl, DCM, oxyl, TAME ja TOL, ja alemmat kuin tavoitearvot seuraaville yhdisteille; TCBz, DCEa, Bz, CCl, ETBz, mpxyl, MTBE, TCEe ja TECEe. Direktiivissä mainittujen yhdisteiden määritysrajojen tulisi olla kolmasosa EQS-arvoista. Tässä pätevyyskokeessa koko aineistossa hyväksyttäviä tuloksia oli yhteensä %. Akkreditoitujen ja akkreditoimattomien määritysten tuloksissa hyväksyttäviä oli saman verran. Vesi- ja maanäytteiden VOC-tuloksissa oli enemmän hyväksyttäviä tuloksia kuin vuoden 00 vastaavassa vertailussa, kun taas synteettisen näytteen tuloksissa hyväksyttäviä tuloksia lähes saman verran.

14 REFERENCES ISO/IEC 0, 0. Conformity assessment General requirements for pro ciency testing. ISO, 00. Statistical methods for use in pro ciency testing by interlaboratory comparisons. Thompson. M., Ellison. S.L. R., Wood. R., 00. The International Harmonized Protocol for the Pro ciency Testing of Analytical Chemistry laboratories (IUPAC). International Union of Pure and Applied Chemistry. Analytical. Applied and Clinical Chemistry Division. Interdivisional Working Party for Harmonization of Quality Assurance Schemes for Analytical Laboratories. ISO 0:, Water quality Determination of highly volatile halogenated hydrocarbons Gas chromatographic methods ISO -:, Water quality - Determination of benzene and some derivatives - Part : Head-space gas chromatographic method ISO 0:00, Water quality Gas-chromatographic determination of number of monocyclic aromatic hydrocarbons, naphthalene and several chlorinated compounds using purge and trap and thermal desorption. ISO :00, Soil quality Gas chromatographic quantitative determination of volatile aromatic and halogenated hydrocarbons and selected ethers Static headspace method. EPA 0A, Closed-system purge-and-trap and extraction for volatile organics in soil and waste samples. EPA 0C, Volatile organic compounds by gas chromatography/mass spectrometry (GC/MS). ISO 00:00, Soil quality Gas chromatographic determination of the content of volatile aromatic hydrocarbons, naphthalene and volatile halogenated hydrocarbons Purge-and-trap method with thermal desorption. Korhonen, K., Sainio, P., Nuutinen, J., Markkanen, A., Tanttu, H. and Ilmakunnas, M., 00, Pro ciency Test SYKE / 00 Oil hydrocarbons and volatile organic compounds in water and soil. Reports of Finnish Environment Institute / 00. ISBN ---- (pdf). /publications.

15 PARTICIPANTS IN THE PT SYKE a/0 Comie stc, Siffano, Italy Ekokem Oy Ab, Riihimäki, Finland Eurofins Environment Sweden AB, Lidköping, Sweden Eurofins Miljø A/S, Vejen, Denmark Eurofins Scientific Finland Oy, Tampere, Finland Finnish Environment Institute, SYKE, Helsinki, Finland Kokemäenjoen vesistön vesiensuojelu ry, Hämeenlinna, Finland Lapin Vesitutkimus Oy, Rovaniemi, Finland MetropoliLab Oy, Helsinki, Finland NabLabs Ympäristöanalytiikka Oy, Oulu, Finland Novalab Oy, Karkkila, Finland Ramboll Analytics Oy, Lahti, Finland SGS Inspection Services Oy, Hamina, Finland APPENDIX

16 APPENDIX / PREPARATION OF THE SAMPLES Each individual stock solution was prepared by weighting methanol ( ml) and from 0. to g of the pure compound into a vial. The concentrations of the analytes in the individual stock solutions have been presented in the table below. The mixture was prepared by weighing from 0. to.0 ml of the individual stock solutions (compounds shown in the table ) into a vial, the final volume of the mixture was. ml. The mixture was prepared by weighing from 0. to. ml of the individual stock solution (compounds shown in the table ) into a vial, the final volume of the mixture was. ml. The mixture was prepared by weighing from.0 to.0 ml of the individual stock solution (compounds shown in the table ) into a vial, the final volume was ml. Table. Concentrations of the stock solutions and the mixtures Compound producer, purity Benzene Fluka,. % Stock solution, mg/ml Mixture mg/ml.. Ethylbenzene Fluka, >. %.0. Toluene Fluka,. % o-xylene Fluka,. %....0 p-xylene Fluka,. %..,,-Trichlorobenzene Fluka,. % Carbontetrachloride Ehrenstorfer,. %.. Mixture mg/ml.. Chloroform Fluka, >. %..,-Dichloroethane Ehrenstorfer,. % cis-,-dichloroethene Fluka, > % Dichloromethane Aldrich, >... Trichloroethene Riedel-de Haën,. %.0. Tetrachloroethene Fluka, >. %.. Mixture mg/ml MTBE Sigma Aldrich,. %..00 TAME Aldrich, %..

17 PREPARATION OF THE SAMPLES APPENDIX / The addition solution was prepared by weighting ml of methanol,. ml of the mixture, 0. ml of the mixture and 0. ml of the mixture into a vial. The sample was prepared by diluting ml of the addition solution with ml methanol (Table ). The addition solution was prepared by weighting ml of the mixture, ml of the mixture and ml of the mixture into a vial. Addition solution was diluted three times with methanol in ratio : (v/v) and the final methanol solution ( ml) was diluted with 0 litre of ground water to get the sample (Table ). The addition solution was prepared by weighting ml of methanol, ml of the mixture, ml of the mixture and ml of the mixture. The sample was made by mixing 0 g of dry soil, ml of water, ml of the addition solution and 0 ml of methanol (Table ). Table. Concentrations of the addition solutions (,, ) and the samples (,, ) Measurement Addition solution mg/ml Addition solution mg/ml Addition solution mg/ml µg/ml Benzene Ethylbenzene Toluene o-xylene p-xylene ,,- Trichlorobenzene Chloroform Carbontetrachloride,- Dichloroethane cis-,- Dichloroethene Dichloromethane Trichloroethene Tetrachloroethene MTBE TAME

18 APPENDIX TESTING OF HOMOGENEITY The homogeneities of the samples and were tested by analysing seven sub samples. Analyte / Sample o-xylene/ o-xylene/,,-tcbz/,,-tcbz/ TECEe/ TeCEe/ MTBE/ MTBE/ Conc. or s p % s p s a s a / s p Was s a / s p < 0.? s bb s bb c Was s bb < c? yes yes yes yes yes yes yes 0.0 < yes yes yes yes yes yes yes yes yes Conc. = Concentration s p = Target deviation, total target deviation / s p % = Target deviation as percent, total target deviation / s a = Analytical deviation, mean standard deviation of results in a sub sample s bb = Between-sample deviation, standard deviation of results between sub samples c = F s all + F s a where: s all = (0. s p ) F =.0 when the number of sub samples is F =. when the number of sub samples is Conclusion: In each case s a / s p < 0. and s bb < c. The samples could be regarded as homogenous.

19 APPENDIX / TESTING OF STABILITY The samples were distributed November 0 and they were asked to analyse before November 0. Sample / concentration µg/ml Analyte Assigned value Nov Nov C Nov C D 0. s p Test pasted? Benzene Yes Ethylbenzene Yes Toluene Yes o-xylene Yes m/p-xylene Yes,,- Trichlorobenzene Carbontetrachloride Yes Yes Chloroform Yes,- Dichloroethane cis-,- Dichloroethene Yes Yes Dichloromethane Yes Trichloroethene Yes Tetrachloroethene Yes MTBE Yes TAME Yes Conclusion: The stability of the samples during the transport was good.

20 APPENDIX / TESTING OF STABILITY The samples were distributed November 0 and they were asked to analyse before November 0. Sample / concentration Analyte Assigned value Nov Nov C Nov C D 0. s p Test pasted? Benzene Yes Ethylbenzene No Toluene No o-xylene Yes m/p-xylene Yes No No Chloroform Yes,,- Trichlorobenzene Carbontetrachloride,- Dichloroethane cis-,- Dichloroethene Yes Yes Dichloromethane Yes Trichloroethene No Tetrachloroethene No MTBE Yes TAME Yes The stability results were within the daily variation of the method and as well as the variation between the bottles. When the samples were delivered to the participants only one laboratory reported the temperature of the samples to be higher than C. The results of this laboratory for the sample were satisfactory (z < ). Conclusion: The stability of the samples during the transport was mainly good.

21 APPENDIX / TESTING OF STABILITY The samples were distributed November 0 and they were asked to analyse before November 0. Sample / concentration Analyte Assigned value Oct Nov C Nov C D 0. s p Test pasted? Benzene Yes Ethylbenzene Yes Toluene Yes o-xylene Yes m/p-xylene Yes,,- Trichlorobenzene Carbontetrachloride Yes Yes Chloroform Yes,- Dichloroethane cis-,- Dichloroethene Yes Yes Dichloromethane Yes Trichloroethene Yes Tetrachloroethene Yes MTBE Yes TAME Yes Conclusion: The stability of the samples during the transport was good.

22 APPENDIX. 0 FEEDBACK FROM THE PARTICIPANTS Lab Comment Action/SYKE all The weight after receiving of the sample VG was asked to report although the initial weight was not given in the covering letter with the samples. The samples arrived to the local bus station November late afternoon. In the sheet of the notification of sample receiving the formula for the calculation of the weight difference-% could be added. Evaporation of water samples is not probable. The delivering time is from to o'clock and it will be written down in the consignment note. This good idea will be taken into account in next PTs.

23 FEEDBACK TO THE PARTICIPANTS APPENDIX. Lab Comments from the provider Method description was lacking. Method description was lacking. The participant sent the results November, but did not inform the provider that the results are not arriving on time.

24 APPENDIX ASSIGNED VALUES AND THEIR UNCERTAINTIES Analyte Abbreviation Benzene Bz Ethylbenzene ETBz Tolune TOL o-xylene oxyl m/p-xylene mpxyl,,-trichlorobenzene TCBz Carbontetrachloride CCl Chloroform CHCl,-Dichloroethane DCEa cis-,-dichloroethene cdcee Dichloromethane DCM Trichloroethene TCEe Tetrachloroethene TECEe MTBE TAME Sample Assigned value Unit Evaluation of the assigned value Uncertainty (U = u c ) %. µg/ml Calculated <.0 Robust mean.. Robust mean.. µg/ml Calculated <. Robust mean. Robust mean. µg/ml Calculated <. Robust mean.. Robust mean.. µg/ml Calculated <. Robust mean.. Robust mean. µg/ml Calculated <. Robust mean. Robust mean. µg/ml Calculated <. Robust mean. Robust mean 0. µg/ml Calculated <. Robust mean. Robust mean. µg/ml Calculated <. Robust mean.. Robust mean..0 µg/ml Calculated <.0 Robust mean. Robust mean. µg/ml Calculated <. Robust mean.. Robust mean.. µg/ml Calculated <. Robust mean. Robust mean. µg/ml Calculated <. Robust mean..0 Robust mean.. µg/ml Calculated <. Robust mean.0 Robust mean.. µg/ml Calculated < 0. Robust mean. Robust mean. µg/ml Calculated <. Robust mean.0 Robust mean

25 LIITE APPENDIX / LIITE. RESULTS OF EACHLABORATORY APPENDIX. Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml 0, yes,,,, 0,0, 0 0 0, yes,,,,0 0,0, 0-0, yes, 0,,, 0,0, 0 0, yes,0, 0, 0, 0,, 0 0, yes,,,,,0, 0 0,0 yes, 0,,, 0, 0, 0-0, yes,,,, 0,, 0-0,0 yes,,,, 0,, , yes, 0,0,, 0,, 0-0, yes,,,, 0,0, 0-0, yes,,,,,, 0 0 0, yes, 0,0,, 0,0, 0,0 yes 0, 0, 0,00 0, 0,,, yes,,,, 0,, 0 0, yes, 0,0,, 0,, 0, yes,,,, 0,, 0 0, yes,,,,,0,,0 yes, 0,,, 0,, 0,00 yes,,,, 0,, 0 0 0, yes,,,,0,0, 0, yes, 0,,, 0,, 0-0, yes,,0,0, 0,, 0-0,0 yes,,,, 0,, 0-0, yes, 0,,, 0,, 0-0, yes,,,,,,0 0-0,0 yes,,,,,0, 0-0, yes, 0,0,0,,, 0-0, yes,,,,0 0,, 0 0, yes 0,,, 0,,, 0 0 0, yes, 0,,,,0, 0 0-0, yes,,,, 0,, 0 0, yes,,,, 0,, 0 0,000 yes, 0,,, 0,, 0 -, yes,,,, 0,, 0-0, yes,,,,, 0 0-0, yes 0,,,,, 0 0 0, yes,,,, 0,, 0 0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 0, yes,,,,0 0,, 0 0, yes,,,,,, 0 0 0, yes,0 0,,, 0,, 0 0, yes,,,0, 0,,0 0 0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

26 LIITE / APPENDIX Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -0,0 yes,,,, 0,0, 0 0 -,00 yes,,,,0 0,0, 0-0, yes, 0,,, 0,0, 0 0-0, yes,0 0, 0, 0, 0,, 0 0,0 yes,,,,,0, 0 0 -,0 yes, 0,0,, 0, 0, 0-0,0 yes,,,, 0,, 0-0, yes,,,, 0,, , yes, 0,0,, 0,, 0-0, yes,,,, 0,0, 0 0,0 yes,,,,,, 0 0-0,0 yes, 0,,, 0,0, 0, yes 0, 0, 0,00 0, 0,,, yes,,,, 0,, 0 0,0 yes, 0,,, 0,, -0,0 yes,,,, 0,, 0 0, yes,,,,,0, -0,00 yes, 0,,, 0,, 0-0, yes,,0,, 0,, 0 0 0, yes,,,,0,0, -0,0 yes, 0,,, 0,, 0 -, yes,,,0, 0,, 0 0, yes,,,, 0,, 0-0,0 yes, 0,,, 0,, 0-0,0 yes,,,,,,0 0,0 yes,,,,,0, 0-0, yes, 0,0,0,,, 0 -, yes,,,,0 0,, 0-0, yes 0,,, 0,,, 0 0-0, yes, 0,,,,0, 0 0-0, yes,,,, 0,, 0 0, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0 -, yes,,,, 0,, 0-0, yes,,,,, 0 0 -,0 yes 0,,,,, 0 0-0, yes,,,, 0,, 0 0, yes,,,,,, 0 0-0,0 yes, 0,,, 0,, 0 0, yes,,,,0 0,, 0 0,0 yes,,,,,, 0 0, yes,0 0,0,, 0,, 0-0, yes,,0,0, 0,,0 0-0,00 yes,,,,,, 0 0-0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

27 LIITE APPENDIX / Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -,0 yes, 0,,, 0,0, 0 0 -,0 yes,,,,0 0,0, 0 -, yes, 0,,, 0,0, 0 0 -, yes,0 0, 0, 0, 0,, 0 -, yes,,,,,0, 0 0 -, yes, 0,,, 0, 0, 0 -, yes,,,, 0,, 0 -, yes,,,, 0,, , yes, 0,,, 0,, 0 -,0 yes,,,, 0,0, 0-0, yes,,,,,, 0 0-0, yes, 0,,, 0,0, 0 -, yes 0, 0,0 0,00 0, 0,, -, yes,,,, 0,, 0 -, yes, 0 0,,, 0,, -,0 yes, 0,,, 0,, 0 -,0 yes,,,,,0, -, yes, 0,,, 0,, 0 -, yes, 0,,, 0,, 0 0-0,0 yes,,,,0,0, -0, yes, 0,0,, 0,, 0 -,0 H,,,0, 0,, 0 -, H,,,, 0,, 0 -, yes, 0,,, 0,, 0 -, yes,,,,,,0 0 -, H,,,,,0, 0 -, yes, 0,,0,,, 0 -, yes,,,,0 0,, 0 0,0 yes 0,,, 0,,, 0 0-0,0 yes, 0,,,,0, 0 0 -, H,,,, 0,, 0 -,0 H,,,, 0,, 0 -,0 yes, 0,,, 0,, 0 -, yes,,,, 0,, 0 -, yes,,,,, 0 0 -, yes 0,,,,, 0 0 -, yes,,,, 0,, 0 -, yes,,,,,, 0 0-0,00 yes, 0,,, 0,, 0 -, yes,,,,0 0,, 0 -, yes,,,,,, 0 0 -,00 yes,0 0,,, 0,, 0 -, yes,,,0, 0,,0 0 -, yes,,,,,, 0 0 -, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

28 LIITE / APPENDIX Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml,0 yes,,,, 0,0, 0 0 -, yes, 0,,, 0,0, 0 0 DCEa µg/ml, yes,0, 0, 0, 0,, 0 -,0 yes, 0,,, 0, 0, 0 Bz µg/ml,0 yes,,,, 0,, 0 -, yes, 0,,, 0,, 0 cdcee µg/ml, yes,,,, 0,0, 0-0, yes, 0,,, 0,0, 0 CCl µg/ml,0 yes 0, 0, 0,00 0, 0,, -0, yes, 0,0,, 0,, CHCl µg/ml, yes,,,, 0,, 0 -, yes, 0,,, 0,, 0 DCM µg/ml, yes,,,, 0,, 0 0 -, yes, 0,,, 0,, 0 ETBz µg/ml, yes,,,0, 0,, 0 -, yes, 0,,, 0,, 0 mpxyl µg/ml, yes,,,,,,0 0-0, yes, 0,,0,,, 0 MTBE µg/ml, yes,,,,0 0,, 0 -, yes, 0,,,,0, 0 0 oxyl µg/ml, yes,,,, 0,, 0 -, yes, 0,,, 0,, 0 TCEe µg/ml, yes,,,, 0,, 0-0, yes, 0,0,, 0,, 0 TECEe µg/ml, yes,,,,0 0,, 0 -, yes,0 0,,, 0,, 0 TOL µg/ml, yes,,0,0, 0,,0 0 -, yes, 0,0,, 0,, 0 TCBz µg/ml 0, yes,,,, 0,0, 0 0, yes,,,,0 0,0, 0 0,0 yes, 0,,, 0,0, 0 0 DCEa µg/ml 0, yes,0,0 0, 0, 0,, 0 0, yes,,,,,0, 0 0 -,0 yes, 0,0,, 0, 0, 0 Bz µg/ml 0, yes,,,, 0,, 0, yes,,,, 0,,0 0 0,0 yes, 0,,, 0,, 0 cdcee µg/ml 0, yes,,,, 0,0, 0,0 yes,,,,,, 0 0 0, yes, 0,,, 0,0, 0 CCl µg/ml H 0, <0, 0,00 0, 0,, -, yes,,,, 0,, 0 -, yes, 0 0,,, 0,, CHCl µg/ml -, yes,,,, 0,, 0 0, yes,,,,,0, -0, yes, 0,,, 0,, 0 DCM µg/ml, yes,,,, 0,, 0 0, yes,,,,0,0,, yes, 0,,, 0,, 0 ETBz µg/ml, yes,,,0, 0,, 0,0 yes,,,, 0,, 0, yes, 0,,, 0,, 0 mpxyl µg/ml, yes,,,,,,0 0, yes,,,,,0, 0, yes, 0,,0,,, 0 MTBE µg/ml -0, yes,,,,0 0,, 0 0, yes 0,,, 0,,, 0 0 0,0 yes, 0,,,,0, 0 0 oxyl µg/ml,0 yes,,,, 0,, 0, yes,,,, 0,, 0,0 yes, 0,,, 0,, 0 TAME µg/ml -, yes,,,, 0,, 0 0, yes,,,,, 0 0 0, yes 0,,,,, 0 0 TCEe µg/ml -, yes,,,, 0,, 0-0,0 yes,,,,,, 0 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

29 LIITE APPENDIX / Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TECEe µg/ml TOL µg/ml TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml oxyl µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -0, yes, 0,,, 0,, 0 0,0 yes,,,,0 0,, 0,0 yes,,,,,, 0 0 0, yes,0 0,,, 0,, 0,0 yes,,,0, 0,,0 0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 -,0 yes,,,, 0,0, 0 0-0, yes, 0,,, 0,0, 0 0-0, yes,0 0, 0, 0, 0,, 0-0, yes, 0,,, 0, 0, 0 -, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0 -, yes,,,, 0,0, 0-0,0 yes, 0,,, 0,0, 0 0, yes 0, 0, 0,00 0, 0,, 0, yes, 0,,, 0,, -, yes,,0,, 0,, 0-0,0 yes, 0,,, 0,, 0 -, yes,,,0, 0,, 0 0, yes, 0,,, 0,, 0 0,0 yes,,,,,,0 0, yes, 0,,0,,, 0-0, yes,,,,0 0,, 0 0, yes, 0,,,,0, 0 0 -,0 yes,,00,, 0,, 0 0,00 yes, 0,0,, 0,, 0 -,0 yes,,0,, 0,, 0-0, yes, 0,,, 0,, 0 -,0 yes,,,,0 0,, 0-0, yes,0 0,,, 0,, 0 -, yes,,,0, 0,,0 0 0, yes, 0,,, 0,, 0,0 yes,,,, 0,0, 0 0 0, yes, 0,,, 0,0, 0 0 0, yes,0,0 0, 0, 0,, 0, H, 0,,, 0, 0, 0 0, yes,,,, 0,, 0,0 H, 0,0,, 0,, 0,0 yes,,,, 0,0, 0, H, 0,,, 0,0, 0, yes 0, 0, 0,00 0, 0,,, H, 0,,, 0,,, yes,,,, 0,, 0,0 H, 0,, 0,, 0, yes,,,, 0,, 0 0,0 H, 0,,, 0,, 0, yes,,,0, 0,, 0,0 H, 0,,, 0,, 0, yes,,,,,,0 0,0 H, 0,0,,, 0, yes,,,, 0,, 0,0 H, 0,,, 0,, 0-0, yes,,,, 0,, 0, H, 0,, 0,, 0, yes,,,,0 0,, 0, H,0 0,,, 0,, 0, yes,,,0, 0,,0 0, H, 0,0,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

30 LIITE / APPENDIX Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -0, yes,,,, 0,0, 0 0-0, yes,,,,0 0,0, 0 0, yes, 0,,, 0,0, 0 0-0,0 yes,0,00 0, 0, 0,, 0-0,0 yes,,,,,0, 0 0 0,0 yes, 0,0,, 0, 0, 0,0 yes,,,, 0,, 0-0, yes,,0,, 0,, , yes, 0,,, 0,, 0, yes 0, 0, 0,00 0, 0,, -, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0, yes,,,, 0,, 0 -,0 yes,,,,,0,, yes, 0,,, 0,, 0 0,0 yes,,,, 0,, 0 0-0, yes,,0,,0,0, 0,0 yes, 0,,, 0,, 0 0, yes,,0,0, 0,, 0-0, yes,,,, 0,, 0, yes, 0,,, 0,, 0, yes,,,,,,0 0-0,0 yes,,,,,0, 0 0, yes, 0,00,0,,, 0, yes,,,,0 0,, 0-0, yes 0,,, 0,,, 0 0 0, yes, 0,,,,0, 0 0 0, yes,,,, 0,, 0-0, yes,,,, 0,, 0,0 yes, 0,,, 0,, 0, yes,,,, 0,, 0, yes,,,,, 0 0, yes 0,,,,, 0 0, yes,,,, 0,, 0-0,0 yes,,,,,, 0 0, yes, 0,,, 0,, 0,0 yes,,,,0 0,, 0-0, yes, 0,,,,, 0 0, yes,0 0,,, 0,, 0,0 yes,,,0, 0,,0 0-0, yes,,0,,,, 0 0 0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

31 LIITE APPENDIX / Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -, yes,0 0, 0, 0, 0,, 0-0, yes,,,,,0, 0 0 -, yes, 0,,, 0, 0, 0-0, yes,,,, 0,, 0 0, yes,,,, 0,, ,0 yes, 0,0,, 0,, 0,0 yes,,,, 0,0, 0 0, yes,,,,,, 0 0-0, yes, 0,,, 0,0, 0, yes 0, 0, 0,00 0, 0,,, yes,,,, 0,, 0-0,0 yes, 0,,, 0,, 0, yes,,,, 0,, 0, yes,,,,,0, -0, yes, 0,,, 0,, 0 0,0 yes,,,, 0,, 0 0 0, yes,,,,0,0, -0, yes, 0,0,, 0,, 0 -, yes,,,0, 0,, 0 -, yes,,,, 0,, 0 0,0 yes, 0,,, 0,, 0 -, yes,,,,,,0 0 -, yes,,,,,0, 0-0,0 yes, 0,,0,,, 0-0, yes,,,,0 0,, 0 0, yes 0,,, 0,,, 0 0-0, yes, 0,,,,0, 0 0 -, yes,,,, 0,, 0-0,0 yes,,,, 0,, 0 0, yes, 0,,, 0,, 0 0, yes,,,, 0,, 0,0 yes,,,,, 0 0-0, yes 0,,,,, 0 0 0, yes,,,, 0,, 0 0, yes,,,,,, 0 0-0, yes, 0,,, 0,, 0 -, yes,,,,0 0,, 0-0, yes,,,,,, 0 0-0, yes,0 0,,, 0,, 0-0, yes,,,0, 0,,0 0 0,0 yes,,,,,, 0 0-0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

32 LIITE / 0 APPENDIX Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -, yes,,0,, 0,0, 0 0, yes,,,,0 0,0, 0 -, yes, 0,,, 0,0, 0 0-0, yes,0 0, 0, 0, 0,, 0 0, yes,,,,,0, 0 0-0, yes, 0,,, 0, 0, 0-0, yes,,0,, 0,, 0, yes,,, 0,, ,0 yes, 0,,, 0,, 0 -, yes,,,, 0,0, 0 0, yes,,,,,, 0 0 0,0 yes, 0,,, 0,0, 0 -, yes 0, 0, 0,00 0, 0,,, yes,,,, 0,, 0-0, yes, 0,0,, 0,, -, yes,,,, 0,, 0 0, yes,,,,,0, 0, yes, 0,,, 0,, 0 0, yes,,,, 0,, 0 0,0 yes,,,,0,0, 0,0 yes, 0,,, 0,, 0-0, yes,,0,0, 0,, 0,0 yes,,,, 0,, 0-0,0 yes, 0,,, 0,, 0-0, yes,,,,,,0 0 0, yes,,,,,0, 0-0, yes, 0,,0,,, 0-0, yes,,,,0 0,, 0, yes 0,,, 0,,, 0 0 0,0 yes, 0,,,,0, 0 0 -, yes,,0,, 0,, 0 0, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0-0,0 yes,,,, 0,, 0,0 yes,,,,, 0 0-0,0 yes 0,,,,, 0 0 -,0 yes,,0,, 0,, 0, yes, 0,,,,, 0 0 0, yes, 0,,, 0,, 0 -, yes,,,,0 0,, 0, yes,,,,,, 0 0-0, yes,0 0,,, 0,, 0-0, yes,,,0, 0,,0 0, yes,,,,,, 0 0-0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

33 LIITE APPENDIX / Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml -,0 yes,,,, 0,0, 0 0, <,0,,0 0,0, 0-0, yes, 0,,, 0,0, 0 0 DCEa µg/ml -, yes,0 0, 0, 0, 0,, 0, yes,,,,,0, 0 0 0, yes, 0,,, 0, 0, 0 Bz µg/ml -, yes,,,, 0,, 0-0,0 yes,,,, 0,, , yes, 0,,, 0,, 0 CCl µg/ml H 0, <,00 0,00 0, 0,,, <0,, 0,, 0 H, 0 <,,, 0,, CHCl µg/ml, H,,,, 0,, 0 H, <,,,0, 0, yes, 0,,, 0,, 0 DCM µg/ml -0, yes,,0,, 0,, 0 0 H, <,,0,0, 0,0 yes, 0,,, 0,, 0 ETBz µg/ml -, yes,,0,0, 0,, 0-0, yes,,,, 0,, 0 0, yes, 0,,, 0,, 0 mpxyl µg/ml -0, yes,,,,,,0 0-0, yes,,,,,0, 0 0,0 yes, 0,0,0,,, 0 MTBE µg/ml -, yes,,,,0 0,, 0-0, yes 0,,, 0,,, 0 0 0,0 yes, 0,,,,0, 0 0 oxyl µg/ml -, yes,,0,, 0,, 0-0, yes,,,, 0,, 0 0, yes, 0,0,, 0,, 0 TAME µg/ml -,0 yes,,00,, 0,, 0-0, yes,,,,, 0 0 0, yes 0,,,,, 0 0 TCEe µg/ml -, yes,,,, 0,, 0-0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 TECEe µg/ml -, yes,,,,0 0,, 0-0, yes, 0,,,,, 0 0 0, yes,0 0,,, 0,, 0 TOL µg/ml -, yes,,,0, 0,,0 0-0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

34 LIITE / APPENDIX Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml -0, yes,,,, 0,0, 0 0-0,0 yes,,,,0 0,0, 0-0,00 yes, 0,,, 0,0, 0 0-0, yes,0,0 0, 0, 0,, 0-0, yes,,,,,0, 0 0-0, yes, 0,,, 0, 0, 0 -,0 yes,,0,, 0,, 0 0,0 yes,,,, 0,, , yes, 0,,, 0,, 0 0, yes,,,, 0,0, 0-0,0 yes,,,,, 0 0, yes, 0,,, 0,0, 0, yes 0, 0, 0,00 0, 0,, 0,0 yes,,,, 0,, 0, yes, 0,,, 0,, -0,0 yes,,,, 0,, 0-0,0 yes,,,,,0, 0, yes, 0,,, 0,, 0 -, yes, 0,,, 0,, 0 0 -, yes,,,,0,0, -0, yes, 0,,, 0,, 0 -, yes,,0,0, 0,, 0 -, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0 -,0 yes,,,,,,0 0 -,0 yes,,,,,0, 0 -, yes, 0,,0,,, 0-0, yes,,,,0 0,, 0-0, yes 0,, 0,,, 0 0, yes, 0,,,0, 0 0-0, yes,,,, 0,, 0 -, yes,,,, 0,, 0-0, yes, 0,,, 0,, 0 -, yes,,,, 0,, 0-0,0 yes,,,, 0 0 0,0 yes 0,,,, 0 0-0, yes,,,, 0,, 0-0, yes,,,,, 0 0 0,0 yes, 0,,, 0,, 0,0 yes,,,,0 0,, 0-0, yes, 0,,,, 0 0-0, yes,0 0,,, 0,, 0 0, yes,,,0, 0,,0 0-0, yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

35 LIITE APPENDIX / Analyte Unit Sample z-graphics Z- value Outl Assigned test OK value * Targ SD% Lab's result Md. Mean SD SD% Passed Outl. failed Missing Num of labs TCBz µg/ml DCEa µg/ml Bz µg/ml cdcee µg/ml CCl µg/ml CHCl µg/ml DCM µg/ml ETBz µg/ml mpxyl µg/ml MTBE µg/ml oxyl µg/ml TAME µg/ml TCEe µg/ml TECEe µg/ml TOL µg/ml, yes,,0,, 0,0, 0 0, yes,,,,0 0,0, 0, yes, 0,,, 0,0, 0 0, H,0, 0, 0, 0,, 0-0, yes,,,,,0, 0 0 -, yes, 0,,, 0, 0, 0,0 H,,,, 0,, 0-0, yes,,,, 0,, ,0 yes, 0,0,, 0,, 0, H,,,, 0,0, 0-0,0 yes,,,,,, 0 0-0, yes, 0,,, 0,0, 0,0 H 0,,0 0,00 0, 0,, -0, yes,,,, 0,, 0-0, yes, 0,,, 0,,, yes,,,, 0,, 0-0, yes,,,,,0, -0, yes, 0,,, 0,, 0,0 yes,,,, 0,, 0 0 -,000 yes,,,,0,0,, H,,0,0, 0,, 0-0, yes,,,, 0,, 0 0, yes, 0,,, 0,, 0,0 C,,,,,,0 0-0, yes,,,,,0, 0, yes, 0,,0,,, 0,0 H,,,,0 0,, 0 -, yes 0,,, 0,,, 0 0-0,0 yes, 0,,,,0, 0 0, H,,0,, 0,, 0-0, yes,,,, 0,, 0, yes, 0,,, 0,, 0, H,,,, 0,, 0 -,0 yes,,,,, 0 0 0, yes 0,,,,, 0 0, H,,,, 0,, 0-0, yes,,,,,, 0 0-0,0 yes, 0,,, 0,, 0, C,,0,,0 0,, 0-0,0 yes,,,,,, 0 0 0, yes,0 0,,, 0,, 0, H,,,0, 0,,0 0-0,0 yes,,,,,, 0 0 0, yes, 0,,, 0,, 0 Outlier test failed: C - Cohcran, G - Grubbs(-outlier algorithm), G - Grubbs(-outliers algorithm), H - Hampel, M - manual SYKE - Interlaboratory comparison test /0

36 LIITE APPENDIX / LIITE. THE RESULTS AND THEIR UNCERTAINTIES GRAPHICALLY APPENDIX. TCBz µg/ml,,,,,,,, 0, TCBz,,,, TCBz,,, SYKE - Interlaboratory comparison test /0

37 LIITE APPENDIX / DCEa,,,, µg/ml 0, 0, 0, DCEa DCEa,,, SYKE - Interlaboratory comparison test /0

38 LIITE APPENDIX / Bz,,, µg/ml,,,,,,, Bz Bz,,,,,, SYKE - Interlaboratory comparison test /0

39 LIITE APPENDIX / cdcee,,,, µg/ml,,,,,, cdcee 0 cdcee,,,, SYKE - Interlaboratory comparison test /0

40 LIITE APPENDIX / CCl 0, 0, 0, 0, µg/ml 0, 0, 0, 0, 0, CCl,,,,, CCl,,,, 0, 0, 0, SYKE - Interlaboratory comparison test /0

41 LIITE APPENDIX / CHCl,,,, µg/ml,,, 0, 0, CHCl CHCl,,, SYKE - Interlaboratory comparison test /0

42 LIITE APPENDIX / 0 DCM,,,, µg/ml, 0, 0, 0, DCM DCM,,, SYKE - Interlaboratory comparison test /0

43 LIITE APPENDIX / ETBz µg/ml,,,,,,,,,, ETBz ETBz,,,,,,, SYKE - Interlaboratory comparison test /0

44 LIITE APPENDIX / mpxyl,, µg/ml,, mpxyl mpxyl SYKE - Interlaboratory comparison test /0

45 LIITE APPENDIX / MTBE,, µg/ml,,, MTBE 0 0 MTBE 0 SYKE - Interlaboratory comparison test /0

46 LIITE APPENDIX / oxyl µg/ml,,,,,,,,,,, oxyl oxyl SYKE - Interlaboratory comparison test /0

47 LIITE APPENDIX / TAME, µg/ml,,, TAME 0 TAME SYKE - Interlaboratory comparison test /0

48 LIITE APPENDIX / TCEe,, µg/ml,,,,, TCEe 0 TCEe SYKE - Interlaboratory comparison test /0

49 LIITE APPENDIX / TECEe,,,, µg/ml,,,,, TECEe 0 0 TECEe SYKE - Interlaboratory comparison test /0

50 LIITE APPENDIX / TOL,, µg/ml, TOL TOL SYKE - Interlaboratory comparison test /0

51 EXPLANATIONS FOR THE RESULT SHEETS Results of each participant (Appendixes and ) Sample The code of the sample APPENDIX z-graphics z score - the graphical presentation z score calculated as follows: z = (x i - X)/s p, where x i = the result of the individual laboratory X = the reference value (the assigned value) s p = the target value of the standard deviation for proficiency assessment Outl test OK yes - the result passed the outlier test H = Hampel test (a test for the mean value) In addition, in robust statistics some results deviating from the original robust mean have been rejected Assigned value the reference value * Targ SD % the target value of total standard deviation for proficiency assessment at the % confidence level, equal s p Lab s result the result reported by the participant (the mean value of the replicates) Md. Median Mean Mean Robust mean Robust mean SD Standard deviation SD% Standard deviation, % SD %rob Robust standard deviation, % Passed The results passed the outlier test Missing i.e. < DL Num of labs the total number of the participants Summary on the z scores S satisfactory ( - z ) Q questionable ( < z < ), positive error, the result deviates more than s p from the assigned value q questionable ( - > z< -), negative error, the result deviates more than s p from the assigned value U unsatisfactory (z ), positive error, the result deviates more than s p from the assigned value u unsatisfactory (z -), negative error, the result deviates more than s p from the assigned value Robust analysis The items of data is 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 * =. median of x i x* (i =,, p) For each x i (i =,, p) is calculated: x * i = x * - if x i < x * - x * i = x * + if x i > x * + x * i = x i otherwise The new values of x * and s * are calculated from: * x xi / p s. * ( 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. Ref: Statistical methods for use in proficiency testing by inter laboratory comparisons, Annex C ISO 00 []. i x ) )

52 APPENDIX. ANALYTICAL METHODS 0 Water Lab Extraction Internal standard Sampling Equipment Reference No extraction No extraction No extraction Toluene-d,-Dichlorobenzene-d Toluene-d, -Trifluorotoluene Headspace GC-MS ISO Headspace GC-MS ISO 0 Toluene-d Headspace GC-MS In house method No extraction Toluene-d Purge & Trap GC-MS SFS-EN ISO 0 No extraction Toluene-d Bromobenzene Headspace GC-MS SFS-EN ISO 0 No extraction Toluene-d Headspace GC-MS In house method No extraction No extraction Toluene-d,-Dchloroethana-d Headspace GC-MS ISO 0 No Headspace GC-FID ISO - No extraction? Headspace GC-MS ISO - EN ISO 0 No extraction Toluene-d Headspace GC-MS In house method Soil Lab Extraction Internal standard Sampling / Injection Equipment Reference Shaking Shaking Toluene-d,-Dichlorobenzene-d Toluene-d -Trifluorotoluene Headspace GC-MS ISO Headspace GC-MS ISO Shaking Toluene-d Headspace GC-MS In house method Shaking Shaking Shaking Heating in headspace vial Shaking? Toluene-d Fluorobenzene Clorobenzene-d,-Dichlorobenzene-d Purge & Trap GC-MS? Purge & Trap GC-MS SFS-ISO Purge & Trap GC-MS EPA 0A EPA 0C Toluene-d,-dichlorobenzene-d Headspace GC-MS? Toluene-d Bromobenzene Headspace GC-MS ISO SFS-EN ISO 0 Shaking Toluene-d Headspace GC-MS ISO Shaking Fluorobenzene Headspace GC-MS ISO Shaking No Headspace GC-FID SFS-EN ISO Shaking Toluene-d Split GC-MS In house method