Analytische Qualitätssicherung Baden-Württemberg

Transcription

1 Analytische Qualitätssicherung Baen-Württemberg Proficiency Test /12 TW O special organic parameters in rinking water acrylamie, epichlororhyrin provie by AQS Baen-Württemberg at Institute for Sanitary Engineering, Water Quality an Soli Waste Management, University of Stuttgart Bantäle 2, 7069 Stuttgart-Büsnau, Germany on behalf of the Ministry of Rural Affairs an Consumer Protection Baen-Württemberg Stuttgart, in March 201

2 Responsibilities: Scientific irector AQS: Dr.-Ing. Dipl.-Chem. Michael Koch PT manager: Dr.-Ing. Frank Baumeister AQS Baen-Württemberg at Institute of Sanitary Engineering, Water Quality an Soli Waste Management at University of Stuttgart Bantäle Stuttgart-Büsnau Germany Tel.: +9 (0)711 / Fax: +9 (0)711 / info@aqsbw.e

3 PT /12 TW O LIST OF CONTENTS GENERAL... 1 PT DESIGN... 1 SAMPLE PREPARATION... 1 SAMPLE DISTRIBUTION... 1 ANALYTICAL METHODS... 2 SUBMISSION OF RESULTS... 2 EVALUATION PROCEDURE... 2 ASSESSMENT... EVALUATION... EXPLANATION OF APPENDIX A... EXPLANATION OF APPENDIX B... EXPLANATION OF APPENDIX C... MEASUREMENT UNCERTAINTY... 6 TRACEABLE REFERENCE VALUES... 7 INTERNET... 9 Appenix A ACRYLAMIDE... A-1 EPICHLOROHYDRIN... A-8 Appenix B Appenix C ACRYLAMIDE... C-1 EPICHLOROHYDRIN... C-10

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5 PT /12 TW O page 1 General This PT was provie in the context of the AQS Baen-Württemberg rinking water PT scheme. In this roun acrylamie an epichlorohyrin were to be etermine. The PT was execute accoring to the recommenations of the German Feeral Environment Agency from December 200. These recommenations for the execution of PTs for the measurement of chemical parameter an inicator parameter for the external quality control of rinking water laboratories (Bunesgesunheitsblatt 6 12, ) require, that rinking water laboratories must emonstrate their competence for all parameters they are accreite for or they want to be accreite for by a successful participation in a PT roun within a cycle of 2- years. The PT was execute an evaluate accoring to the requirements of DIN 82- A an ISO/TS PT esign Each participant receive the following samples: samples for the etermination of acrylamie in 1000-ml-glass bottles with screw cap. The samples were preserve by cooling. samples for the etermination of epichlorohyrin in 1000-ml-glass bottles with screw cap. The samples were preserve by cooling. ifferent concentration levels/batches were prouce. All participants receive the same samples. Sample preparation The samples for the etermination of the parameters acrylamie an epichlorohyrin were base on a real rinking water matrix. The rinking water was filtere by using µm an 1 µm filter cartriges to eliminate particles. To reuce germs, the rinking water was irraiate with ultraviolet light an pasteurise at 80 C in a stainless steel vessel ove rnight. During pasteurisation, the rinking water was aerate with a mixture compose of carbon ioxie an nitrogen to prevent calcium carbonate precipitation. The rinking water was spike with stock solutions an the concentrations covere rinking an groun water relevant ranges. Dimethylformamie as solvent was ae in a concentration of about 0,2 µl/l to the samples for the etermination of acrylamie an iisopropyl ether in the same concentration for the etermination of epichlorohyrin. The samples were coole irectly after preparation an were shippe by aing freezer packs. Sample istribution The samples were ispatche on 2 th September 2012 by express service.

6 PT /12 TW O page 2 Analytical methos The participants were free to choose a suitable metho, but following limits of quantification were require. parameter acrylamie epichlorohyrin limit of quantification 0,0 µg/l 0,0 µg/l The participants were informe that the samples ha to be analyse in the own laboratory, with own personal an own equipment. Subcontracting of the analysis was not allowe. The samples ha to be analyse in uplicate over the complete metho (sample preparation an measurement). The participants were aske to report the results for acrylamie an epichlorohyrin as average values in µg/l with one igit more than the stanar requires. Submission of results The ealine for the submission of results was on 1 th October Evaluation proceure The statistical evaluation was execute accoring to DIN 82-A an ISO TS Interlaboratory comparisons for proficiency testing of analytical chemistry laboratories. From the participants results a relative stanar eviation was calculate for each concentration level an parameter using the Q-metho. The reference values (see chapter Traceable reference values ) were use as assigne values x a. The stanar eviation resulting from the Q-metho was use as σ ). σ ) was limite as follows: parameter limit for ) σ in % lower limit upper limit acrylamie 2 epichlorohyrin 2 A z-score was calculate for each measurement result erive from the assigne value x a an the stanar eviation for proficiency assessment σ ) : result z score = σˆ x a The z-score was moifie to a z U -score with a correction factor for proficiency assessment (as escribe in the stanars mentione above). The tolerance limit was efine as Iz U I=2,0.

7 PT /12 TW O page Assessment There was no overall assessment of the proficiency test roun, but the single parameters were assesse. A parameter was assesse as successful, if more than half of the values were correctly etermine (2 out of values are within the tolerance limits). Not successful were: 1) Values which were not etermine (if the other samples of this parameters were analyse), 2) Values, which were inicate with lower than limit of quantification, ) Values, which were subcontracte, ) Values, which were submitte after the ealine of submission of results. Evaluation Number of participants: 1 laboratories i not report any result. Number of reporte values: 171 Number of accepte values: 1 (77,78 %) In the following figure the successful an not successful laboratories for each parameter are illustrate.

8 PT /12 TW O page Explanation of Appenix A Appenix A contains for each parameter - parameter tables - a figure of participants means versus the spike amounts for the etermination of the recovery rate an the matrix content - a figure of the relative stanar eviations versus the concentrations - a figure of the tolerance limits in the PT versus the concentrations - the frequency of application of analytical methos - the metho specific evaluation - a comparison of mean an reference values for each concentration level - a comparison of the relative stanar eviations of the ifferent methos - the statistical characteristics of the metho specific evaluation - a tabular comparison of the means with the reference values an their uncertainties Parameter tables In these tables the following values for each concentration level are liste: assigne value expane uncertainty of the assigne value in %, calculate accoring to ISO 128 using the formula rel. stanar eviation U = number of values stanar eviation, calculate using robust statistical metho stanar eviation for proficiency assessment for the calculation of z U -scores rel. stanar eviation for proficiency assessment tolerance limits above an below permitte eviations above an below in % number of values in this level number of not satisfactory values below an above the assigne value an the percentage of these values in total. Determination of recovery rate In the iagrams of the assigne values versus the spike amount of analyte a linear regression line was calculate using a generalize least square regression which takes into account the uncertainties of the values in both irections. From these values the recovery rate for each parameter was etermine (see iagrams). The slope of the line inicates the average recovery rate. The iagrams also contain the expane uncertainty (k=2) of the concentrations from the spike an the assigne values. Relative stanar eviations an tolerance limits The iagrams for the relative stanar eviation vs. the assigne value show the concentration epenency of the stanar eviation an the tolerance limits in percent. The relative stanar eviations calculate from participants ata are the stars connecte by an interrupte line, the rel. stanar eviation taken from the variance function (an sometimes limite by the upper or lower limit) are given by squares, connecte by a continuous line.

9 PT /12 TW O page Metho specific evaluation For each parameter the methos use by the participants are shown in a iagram. In a secon iagram for each metho with a frequency of more than %, values are sorte in categories: too low results with z U -score < -2 low results with 2 z U -score < 1 correct results with 1 z U -score +1 high results with +1 < z U -score +2 too high results with z U -score > +2 Comparison of means an reference values for each concentration level Finally the mean value calculate from all results, the reference value (see chapter Traceable reference values) are compare with mean values calculate for all methos separately. All mean values were calculate using the Hampel estimator escribe in ISO/TS Mean values were calculate only, if more than 8 results were within a z-score-range of ± 2. The means are reporte with their expane uncertainty, calculate accoring to ISO 128. All mean values an their expane uncertainties are aitionally compare with the reference values an their expane uncertainties. Explanation of Appenix B Participants were aske to report expane uncertainties of their results on a voluntary basis. In this iagram for each parameter the reporte uncertainties for all concentration levels with the reproucibility stanar eviation (horizontal line) are isplaye. Values which eviate from the reproucibility stanar eviation with a factor more than 2 are usually not realistic. Explanation of Appenix C In the last part of the report, for all concentration levels the results of all participants are illustrate. Confientiality of participants is ensure by using lab coes. The lab coes were sent to participants with the certificates. In etail Appenix C contains: - a table with all ata - figures with o all reporte results o all z U -scores o all reporte expane uncertainties o all ζ scores Table with all ata The assigne value with the expane uncertainty an the tolerance limits for the concentration level is illustrate in the table. For each participant the following ata are given: lab coe reporte result measurement uncertainty of the value (if reporte) ζ-score for this value, calculate with the following formula ζ = x x u 2 lab a + u 2 ref, with

10 PT /12 TW O page 6 x x a = ifference from the measure value an the assigne value u lab = stanar uncertainty of the value, reporte by the participant u ref = stanar uncertainty of the assigne value z U -score for proficiency assessment assessment of the value accoring to its z-score Meaning of ζ-scores: The assessment of ζ-scores is similar to that of z U -scores. If the ata are normally istribute an the uncertainties are well estimate, ζ-scores will lie between -2 an +2 with a probability of aroun 9 %. ζ-scores are mainly influence by the measurement uncertainties reporte by the laboratory. Therefore ζ-scores are usually not appropriate for the assessment of the reporte results, unless the reporte measurement uncertainty is checke for fitnessfor-purpose. Therefore we o not use the ζ-scores for the assessment of the laboratories. Nevertheless ζ-scores are appropriate to check the plausibility of the reporte measurement uncertainty: If the z U -score of a result is within the tolerance limit an the ζ-score is outsie, then the measurement uncertainty is unerestimate. If the z U -score is outsie the tolerance limits an the absolute value of the ζ-score is lower than two, then the requirements of the proficiency test were stronger compare with the reporte measurement uncertainty. Diagrams of uncertainty ata In the first figure for all lab coes the measurement uncertainty (together with the reproucibility stanar eviation) is illustrate. The secon figure shows the associate ζ-scores. Measurement uncertainty 16 (,2%) out of 7 laboratories with vali values reporte measurement uncertainties. In total 71 (2,%) out of 168 vali values were given with the measurement uncertainty. The following table isplays the number of values with measurement uncertainty against the accreitation status. Accreitation status of the values Number of values Number of values with measurement uncertainty accreite 10 2 (%) not accreite 6 20 (,6%) not specifie 27 9 (,%) We woul like to put emphasis on the fact that reporting of measurement uncertainties in our PT scheme is absolutely voluntary. The only objective is to help all participants to reasonably hanle measurement uncertainties an their estimation. The iagrams show that the sprea of reporte uncertainties in some cases is vast, from unrealistic low values up to very high. A plausibility check using reproucibility stanar eviations of the PT roun coul be helpful here. If measurement uncertainties are unerestimate values assesse as satisfactory in the PT ( z U 2), will have a large ζ-score. ζ > 2 means that the own requirements (efine in terms of estimate uncertainty) are not fulfille. 18 (1%) of the 8 values reporte with uncertainties an having a z U -score z U 2.0 ha a ζ-score > 2.0. This means that the requirements of the PT scheme have been fulfille, but not the own requirements, the uncertainty is unerestimate.

11 PT /12 TW O page 7 Traceable reference values Traceability of analytical results to national an international references is of increasing importance in all laboratories. This is not easy to realise for chemical analyses an often can only be one by analysing certifie reference materials. But availability of these reference materials in the water sector is very limite. Therefore we try to provie reference values for the proficiency test samples, traceable to national an international references. Since our PT samples without exception are spike, real water samples, reference values can be calculate from the sum of matrix content an spike amount of analyte. For both summans traceable values an their uncertainty have to be etermine. Thereby we assume that no unrecognise bias resulting from sample preparation an transport is present an that we recognise all uncertainty components. Determination of the spike amount an its uncertainty All spiking of samples was controlle gravimetrically. Conversion to concentration was one by measuring the ensity of the resulting samples using a pycnometer. This proceure allows the preparation of a complete uncertainty buget. The first step is the specification of the measuran with a formula. This shows the links between the result an all influence quantities for the parameter. with: c lot m subst_ss m ss_iluta m ss_ilutb m ilut_lot m ss m iluta m ilutb m lot ρ lot P F K concentration of the analyte in the lot resulting from the spike in g/l mass of substance ae for preparation of the stock solution in g mass of stock solution ae into the ilution A in g mass of ilution A ae into the ilution B in g mass of ilution B ae into the lot in g total mass of stock solution in g total mass of ilution A in g total mass of ilution B in g total mass of the lot in g ensity of the lot in g/l purity of the use substance conversion factor buoyancy correction Base on this formula the uncertainty buget can be prepare an all components can be quantifie. The following figure shows a typical istribution of the contributions for acrylamie. The main contribution results from the purity of the chemical.

12 PT /12 TW O page 8 All weighings were one as ifference weighings. The precision of these weighings was etermine in experiments by multiple (20fol) measurements of mass pieces with similar masses as a type A uncertainty. The trueness of the weighing, that has to be consiere twice for each weighing, was taken from the calibration certificate of the balance. Maintaining of these tolerances is assure by regular maintenance of the balances by a calibration laboratory an by supervision with our mass pieces (calibrate by an accreite calibration laboratory). The etermination of the ensity was also mae using weighings (of the pycnometer). The above sai also applies here. Temperature measurement was mae with a calibrate thermometer. The purity of the use acrylamie was taken from the certificate of the supplier (99%). The measurement uncertainty with 0,% (expane uncertainty) was also taken from the certificate. With all these uncertainty components the combine uncertainty, as escribe in the EURACHEM/CITAC-Guie Quantifying Uncertainty in Analytical Measurement, was calculate using the sensitivity coefficients etermine by partial erivation of the formula to the respective influence quantities. So traceability was assure by using calibrate balances an thermometers.

13 PT /12 TW O page 9 Determination of the matrix content Because the same matrix was use for preparation of all samples, the matrix content coul be calculate from the mean values of the participants an the spike amounts in a stanar-aition-like way 1,2. The uncertainties of the spike amounts were known from the uncertainty bugets. The expane uncertainties of the mean values of participants result were calculate accoring to ISO 128 (Statistical Methos for Use in Proficiency Testing by Interlaboratory Comparisons) as u mean with: = 2 1, 2 s R n s R reproucibility stanar eviation n number of ata for this level 2 coverage factor for the expane uncertainty 1,2 correction factor (accoring to ISO 128 to be use for robust methos) The content of the matrix can be erive from a linear regression of means vs. spike amounts. Since uncertainties of all ata points were available for x- as well as y-irection a generalise least square regression was use as escribe in DIN EN 61. The computer program B_LEAST (from BAM) was use for this purpose. With this metho a value for matrix an its uncertainty are obtaine. Because of statistical variation of the input values the calculate matrix content might result in a negative value. From a scientific point of view this of course is nonsense. In those cases the matrix content is set to zero. The lower en of the uncertainty range of the matrix content also might be negative. Therefore the expane uncertainty of the matrix content was set to the matrix content itself in this case. The matrix content is not irectly traceable to national or international references, but it oes not consierably compromise the traceability of the final content ue to its comparably low contribution. Internet The report is available on the following webpage: 1 Rienitz, O., Schiel, D., Güttler, B., Koch, M., Borchers, U.: A convenient an economic approach to achieve SI-traceable reference values to be use in rinking-water interlaboratory comparisons. Accre Qual Assur (2007) 12: Koch, M., Baumeister, F.: Traceable reference values for routine rinking water proficiency testing: first experiences. Accre Qual Assur (2008) 1:

14 acrylamie level assigne value [µg/l] expane uncertainty of the assigne value [%] stanar eviation, calculate using robust statistics [µg/l] stanar eviation for proficiency assessment [µg/l] stanar eviation for proficiency assessment [%] upper tolerance limit [µg/l] lower tolerance limit [µg/l] upper tolerance limit [%] lower tolerance limit [%] number of results out below out above 1 0,161 0,6 0,090 0,08 2,00 0,277 0,089 7,99 -,19 27,2 2 0,971 0,6 0,1101 0,099 2,00 0,627 0,2177 7,99 -, ,8 0,706 0,6 0,11 0,191,2 1,069 0,16 1,6-1, ,1 sum ,0 out [%] Recovery an matrix content e e e n e e e n Slope of the regression: 0,972, recovery: 97,2% Neg. x-axis intercept = matrix content: 0 µg/l Expane uncertainty of the matrix content: 0,01 µg/l = 0% page A-1 of page A-1

15 Relative stanar eviation an tolerance limits l e e e n The stanar eviations, calculate with the Q-metho, reache the upper limit with two concentration levels. e e l e e e e n page A-2 of page A-1

16 Metho specific evaluation e ee e,w>d^d^,w>d^d^^w K e e e l Others HPLC-MS/MS - SPE HPLC-MS/MS - irect injection The ifferences between the methos were not significant. page A- of page A-1

17 Comparison of means an reference values level mean [µg/l] exp. uncertainty [µg/l] exp. uncertainty [%] reference value [µg/l] exp. uncertainty [µg/l] exp. uncertainty [%] 1 0,182 0,028 19,2 0,161 0,0010 0,6 2 0,8 0,00 1,8 0,971 0,002 0,6 0,6720 0, ,8 0,706 0,00 0,6 e e n e e,w>d^d^,w>d^d^^w page A- of page A-1

18 n,w>d^d^,w>d^d^^w e e e n,w>d^d^,w>d^d^^w page A- of page A-1

19 e l,w>d^d^,w>d^d^^w HPLC-MS/MS - irect injection level robust mean [µg/l] exp. unc. of the mean [µg/l] exp. unc. of the mean [%] robust stanar eviation [µg/l] 1 0,16 0,0 16,2 0,068 0, , 2 0, 0,07 10,82 0,116, , 0,67 0,07 8,1 0,172 2, ,1 robust stanar eviation [%] number of results out below out above out [%] page A-6 of page A-1

20 HPLC-MS/MS - SPE level robust mean [µg/l] exp. unc. of the mean [µg/l] exp. unc. of the mean [%] robust stanar eviation [µg/l] robust stanar eviation [%] number of results out below out above out [%] 0,688 0,072 10,2 0,172 2, ,11 page A-7 of page A-1

21 epichlorohyrin level assigne value [µg/l] expane uncertainty of the assigne value [%] stanar eviation, calculate using robust statistics [µg/l] stanar eviation for proficiency assessment [µg/l] stanar eviation for proficiency assessment [%] upper tolerance limit [µg/l] lower tolerance limit [µg/l] upper tolerance limit [%] lower tolerance limit [%] number of results out below out above 1 0,1871 0,69 0,086 0,068 2,00 0,6 0,1026 7,99 -,19 1,0 2 0,66 0,69 0,166 0,1166 2,00 0,768 0,26 7,99 -, ,1 0,9602 0,69 0,228 0,21 2,00 1,17 0,26 7,99 -, ,7 sum , out [%] Recovery an matrix content e e e e n e e n Slope of the regression: 0,77, recovery: 7,7% Neg. x-axis intercept = matrix content: 0,0 µg/l Expane uncertainty of the matrix content: 0,0 µg/l = 100% page A-8 of page A-1

22 Relative stanar eviation an tolerance limits e l e e n The stanar eviations, calculate with the Q-metho, reache the upper limit with all concentration levels. e e l e e e n page A-9 of page A-1

23 Metho specific evaluation e eee e e ee 'D^ K ' e l Others GC-MS page A-10 of page A-1

24 Comparison of means an reference values level mean [µg/l] exp. uncertainty [µg/l] exp. uncertainty [%] reference value [µg/l] exp. uncertainty [µg/l] exp. uncertainty [%] 1 0,1768 0,00,7 0,1871 0,001 0,7 2 0,78 0, , 0,66 0,002 0,7 0,708 0,1127 1,0 0,9602 0,0066 0,7 'D^ n page A-11 of page A-1

25 'D^ n 'D^ e n e page A-12 of page A-1

26 e l 'D^ GC-MS level robust mean [µg/l] exp. unc. of the mean [µg/l] exp. unc. of the mean [%] robust stanar eviation [µg/l] 1 0,166 0,018 10,8 0,067, ,6 2 0,77 0,06 9,8 0,1, ,091 0,7 0,01 6,8 0,19 2, ,091 robust stanar eviation [%] number of results out below out above out [%] page A-1 of page A-1

27 el l l l l l l el el l l l el el l l l page B-1 of page B-1

28 assigne value [µg/l]* upper tolerance limit [µg/l] acrylamie - 1 0,161 0,277 ± 0,001 lower tolerance limit [µg/l] 0,0891 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 0,19 0, ,1-0, + 0,8 0,10,2,7-1,16 0,8, 21,1-0,16 0,02-0, -0, ,207 0, ,1-0, ,217 1, ,18 0,0 0,8 0, + 1 0,0 -,0-1 0,067-2,6-16 0,181 0, ,0 -,0-18 0,17 0,0 0, 0,1 + 0,11 0,0-0,8-0, + 2 0,12 0,0-2,8-0,8 + 0,102 0,01 -,9-1,7 + 0,2, - 0,1 0,0-1, -0,9 + 0,17 0, + 6 0,166 0,0 0,2 0,1 + 0,17 0,0-1,0-0, ,16-0, ,111 0,017-6,1-1, + 0,12-0, ,16 0, ,201 0,8 + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C-1 of page C-18

29 n e e h page C-2 of page C-18

30 e e n e ^ ζ e e page C- of page C-18

31 assigne value [µg/l]* upper tolerance limit [µg/l] acrylamie - 2 0,971 0,627 ± 0,002 lower tolerance limit [µg/l] 0,2177 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 0,89 0, , -0,6 + 0,81 0,11 1, 0,7 + 1,8 0,7 2,9 9, - 0,1 0,0 0,6 0, ,1 1, ,12-0, ,8 0, + 1 0, 1, + 1 0,27-1, + 1 0,16-2,6-16 0,97 0, ,0802 -, ,1 0,1 0, 0,1 + 0, 0,06 0,2 0, ,1 0,072 1,2 0, + 0,6 0,109-0,6-0, + 0,16-2,6-0,1 0,17 0,2 0,1 + 0,7-0, + 6 0,6 0,08 1, 0, + 0,2 0,1-0,9-0, + 1 0,2-0, ,279 0,02 -,6-1, + 0,7-0, + 7 0,8 0, + 8 0, 0, + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C- of page C-18

32 e n e e e e h e page C- of page C-18

33 e e ne ^ ζ e e page C-6 of page C-18

34 assigne value [µg/l]* upper tolerance limit [µg/l] acrylamie - 0,706 1,069 ± 0,00 lower tolerance limit [µg/l] 0,16 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 0,70 0, ,8-0,9 + 0,02 0,17 -,0-1, + 1, 0,7 2,0,8-0,68 0,07-0,8-0, ,7 0, ,626-0, ,7-0, ,89 0,07,2 1, ,8-0, ,2-2,7-16 0,70 0, ,079 -, ,66 0,17-0, -0, + 0,66 0,09-0,9-0, + 2 0,78 0,12 0,7 0,2 + 0,9 0,16-2,0-1,1 + 0,66-0, + 0,7 0,2 0, 0,2 + 0,82 0, ,8 0,2 1,0 0,7 + 0,692 0,0-0,6-0, ,62-0, ,6 0,08 -, -1,0 + 0,62-0, + 7 0,791 0, + 8 0,82 0,6 + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C-7 of page C-18

35 e n e e h page C-8 of page C-18

36 e e ne e ^ ζ page C-9 of page C-18

37 assigne value [µg/l]* upper tolerance limit [µg/l] epichlorohyrin - 1 0,1871 ± 0,001 0,6 lower tolerance limit [µg/l] 0,1026 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 0,201 0, + 2 0,217 0,6 + 0,11 0,0 -,7-1,8 + 0,1 0,07-1,6-1, + 0,09 0,02-9,7-2, - 6 0,1 0,08-1,8-0, ,2 1, , 0, , 0,1,1,7-1 0,117-1, ,1-2,1-17 0,06 -,0-20 1,00 0,,1 1,0-21 0,12-1,6 + 0,187 0,0 0,0 0, ,18 0,0-0,1-0, ,2 0, ,19 0,1 + 0,17 0,02-0, -0, + 0 0,171-0, + 7 0,62,1-0,126 0,02-6,1-1, + 1 0,2 0, , 2,6-0,06-2,9-6 0,08 0,09 2,7 2,2-7 0,176-0, + 8 0,17-0, + 9 0,1 0,0 -,8-1, + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C-10 of page C-18

38 e e n e e e h page C-11 of page C-18

39 e n e ^ ζ e e page C-12 of page C-18

40 assigne value [µg/l]* upper tolerance limit [µg/l] epichlorohyrin - 2 0,66 ± 0,002 0,768 lower tolerance limit [µg/l] 0,26 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 0,1 0, + 2 0, -0, + 0,17 0,09 -,1-1, + 0, 0,17-1,6-1, + 0,2 0,0-9, -2,2-6 0,67 0,02 -,7-1, , -1, ,2 0, + 1 0,7 0,1 0,1 0, ,201-2, - 1 0,1 -,2-17 0,1 -,1-20 0,28 0,1 -, -2,2-21 0,2-0, + 0, 0,08-1,7-0, ,9 0,1-0, -0, ,1 0, ,7-0,9 + 0,98 0,119-1,1-0, ,9-0, ,87 2,7-0,1 0,0-11,6-1, ,60 1, ,8 0,1 + 0,27-1, ,17 0,0-12, -2,9-7 0,66 0, , 0, + 9 0, 0,0-11,0-1,6 + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C-1 of page C-18

41 e e e e n h page C-1 of page C-18

42 e e n e e ^ ζ e e page C-1 of page C-18

43 assigne value [µg/l]* upper tolerance limit [µg/l] epichlorohyrin - 0,9602 ± 0,0066 1,17 lower tolerance limit [µg/l] 0,26 lab coe result [µg/l] ± ζ-score z U -score assessm. 1 1,02 0, ,0 0, + 0,79 0,2-1,7-0,9 + 0,69 0, -1, -1,2 + 0,8 0,1-9,6-2,2-6 0,816 0,098-2,9-0, ,72-1, ,97 0, ,8 0,2-1,1-0, ,0 -,0-1 0,8-2,2-17 0,2 -, ,12 0,7-1,6-2, ,9-0,1 + 0,8 0,16-1,6-0, ,87 0,28-1,0-0, ,9-0, ,76-0,9 + 0,797 0,29-1, -0, ,76-0, ,19 0,7 + 0,70 0,07-7, -1, , -2, - 2 0,88-0, + 0,91-1, ,1 0,16 -, -2, ,967 0, , ,69 0,0-17,6-1,2 + * The state uncertainty of the assigne value is the expane uncertainty with a coverage factor k=2 corresponing to a confience level of about 9% page C-16 of page C-18

44 e n e e h page C-17 of page C-18

45 e e ne ^ ζ page C-18 of page C-18