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Quality Documentation

August 2012

Proficiency test SPIL-2 (2012) Nitrogen parameters in wastewater (synthetic wastewater, effluent)

Proficiency test SPIL-2 (2012) Quality documentation August 2012

Smedeskovvej 38, DK-8464 Galten, Denmark Tel: +45 7022 4266 Fax: +45 7022 4255 e-mail: [email protected] Web: www.eurofins.dk

Client

Environmental laboratories

Client’s representative

Project

Proficiency test SPIL-2 (2012)

Project No

20404-22

Authors

Ulla Lund

Date 2012-08-28

Approved by Carsten Theisen Pedersen

Quality Documentation UOL CTP 20130520

Revision Description By Approved Date

Key words Analytical quality, assigned value, precision, accuracy, homogeneity, stability, total nitrogen, ammonium, nitrite+nitrate, conductivity, pH, wastewater

Classification

Open

Internal

Proprietary

Distribution No of copies

DANAK Eurofins:

Ulla Lund, Stine Ottsen

fil fil

mailto:[email protected]

www.eurofins.dk

CONTENTS

1 INTRODUCTION ........................................................................................................ 1-1

2 FEATURES OF THE PROFICIENCY TEST ............................................................... 2-1 2.1 Sample preparation .................................................................................................... 2-1 2.2 Statistical analysis of participants’ data ...................................................................... 2-1 2.3 Assigned and spike value ........................................................................................... 2-1 2.3.1 Assigned and spike values ......................................................................................... 2-2 2.3.2 Test of spike values ................................................................................................... 2-2 2.3.3 Test of assigned values .............................................................................................. 2-2

3 HOMOGENEITY AND STABILITY OF SAMPLES ...................................................... 3-1

4 CONCLUSION ........................................................................................................... 4-1

5 REFERENCES .......................................................................................................... 5-1 APPENDICES A List of participants ..................................................................................................... A-1 B Sample preparation ................................................................................................... B-1 C Control of spike value ................................................................................................ C-1 D Control of recovery .................................................................................................... D-1 E Concentration level ................................................................................................... E-1 F Homogeneity and stability ......................................................................................... F-1

1-1

1 INTRODUCTION

A proficiency test on the analysis of nitrogen parameters in wastewater was conducted on 24 May 2012. The proficiency test was organised by Eurofins Miljø A/S.

The present report contains Eurofins’ documentation for the quality of the proficiency test. Results of the proficiency test including data from participating laboratories and statistical analysis of these data were issued in a report to all participants and DANAK /1/ on 25 June 2012.

2-1

2 FEATURES OF THE PROFICIENCY TEST

Participants in the proficiency test were a total of 65 laboratories from Denmark, the Faroe Islands, Norway, and Sweden. A list of participants is shown in Appendix A.

The closing date for submission of results was 11 June 2012. All participants had sub-mitted their results before the dead-line.

2.1 Sample preparation

The parameters covered in the proficiency test are listed in Table 2 as are the abbrevi-ations used in this report.

Four samples were dispatched for the proficiency test. The samples were sample pairs covering the parameters as described in Table 1. The matrix of the samples represent-ed wastewater, in this case synthetic wastewater, effluent. Sample preparation is de-scribed in Appendix B.

Table 1 Samples in the proficiency test Sample name Parameters A1/B1 TN, NH4, NO2+3, γ25 A2/B2 pH

2.2 Statistical analysis of participants’ data

A split-level design was used. The data analysis was performed in accordance with ISO 5725: “Accuracy (trueness and precision) of measurement methods and results” (1994) /2/ and as described in detail in Spliid (1992) /3/. A short introduction to the sta-tistics and a list of symbols and abbreviations used is given in Eurofins document “Schedule for a proficiency test”, which is available at Eurofins’ home page /4/.

The statistical model used is based on the assumption that the variances for the two samples in a sample pair are identical. The assumption was tested (F-test, 95% confi-dence level) and the result was that the two variances may be assumed to be identical for all parameters.

2.3 Assigned and spike value

An overview of the concentrations in the samples (the assigned values) and the differ-ence in concentration between the two samples of a sample pair (spike value) are shown in Table 2 compared to the range of concentrations normally encountered in synthetic wastewater, effluent. The table also gives the expanded uncertainty of the assigned values.

2-2

Table 2 Assigned and spike value

Parameter Abbreviation Unit Typical Range

Assigned value

Uncertainty of assigned value

Spike value

total nitrogen TN mg/L N 2 - 10 4.09 0.033 0.56 ammonium NH4 mg/L N 0.1 – 2 1.01 0.015 0.15 nitrite+nitrate NO2+3 mg/L N 1 – 5 1.87 0.024 0.25 conductivity γ25 mS/m 50 – 300 111.5 0.43 12.9 pH pH 6 - 9 7.46 0.0098 0

2.3.1 Assigned and spike values The content of each parameter in each sample is given an assigned value for the sam-ple with the lower content and a spike value, the spike value being the difference in concentration between the two samples of the sample pair. The assigned and spike values are both calculated from sample preparation except for conductivity and pH where the assigned value is a consensus value for all laboratories based on the medi-an and the spike value the difference between median values for the two samples in the sample pair.

2.3.2 Test of spike values A comparison was made (t-test, 95% confidence level) between the spike value and the difference in concentration between the two samples in the sample pair found from the laboratories’ results, see Appendix C. The test showed no significant difference be-tween the two except for TN and NO2+3. For TN there was no significant difference when analysing data from laboratories using the method prescribed in legislation (methods no.1, 2 and 3). Method no. 71 for NO2+3 has on previous occasions /7/ shown significantly lower results than other methods. When this method is excluded there is no longer any significant difference between the spike value calculated and the differ-ence between the two samples found by participants.

2.3.3 Test of assigned values The assigned value and the average of the results obtained from all laboratories were also compared (t-test, 95% confidence level), see Appendix D. The test showed no significant difference between the two for all parameters except TN and NO2+3. These differences can be explained by the same causes as described above for the spike value. The assigned values are therefore kept unchanged.

3-1

3 HOMOGENEITY AND STABILITY OF SAMPLES

The homogeneity and stability of samples were tested using the following parameters as indicators:

NH4 Combined homogeneity and stability test

NO2+3 Combined homogeneity and stability test

pH Homogeneity test

The results of control measurements are shown in Appendix F. The appendix also gives the results of the statistical evaluation of the control data. The data are analysed by analysis of variance (ANOVA) giving:

1. the standard deviation/variance for replicates (the contribution from analytical vari-ability),

2. the between bottle standard deviation/variance (the contribution from heterogenei-ty) and

3. the between days concentration difference (the contribution from instability).

Homogeneity is evaluated by comparing the between bottle variance to 0.15 * the max-imum tolerated deviation from the assigned value specified by the Danish EPA /5/ (“sigma” in the calculations is 0.5 times the maximum tolerated deviation), whereas the stability is evaluated by comparing the concentration change of the samples to 0.15 * the maximum tolerated deviation from the assigned value specified by the Danish EPA /5/. This test ensures that heterogeneity and instability will not have negative influence on the evaluation of participant performance /6/.

The appendix also shows the standard deviation within and between laboratories from the proficiency test to allow comparison between tests performed and average quality from participating laboratories.

The tests for stability and homogeneity show that the samples are in general stable and homogeneous.

4-1

4 CONCLUSION

The quality control performed, including test of sample stability and homogeneity as well as test of recovery of spike and assigned values, shows that the samples and their assigned values are suitable for testing the proficiency of the participating laboratories for all parameters. The results are also suitable for estimation of the general quality of analyses among all participating laboratories.

The evaluation of recovery of spike and assigned value for TN is performed using only data from laboratories using the method prescribed by the Danish EPA. When all methods are taken into account there is a significant difference for between both differ-ence between sample pairs and overall average and the spike and assigned values.

Method no. 71 for NO2+3 gives low values and therefore this method is not included in the evaluation of recovery of spike and assigned values.

5-1

5 REFERENCES

/1/ Eurofins A/S, Proficiency test SPIL-2 (2012), Report to participants, June 2012. /2/ ISO 5725-2, Accuracy (trueness and precision) of measurement methods and re-

sults – Part 2: Basic method for the determination of repeatability and reproduci-bility of a standard measurement method, 1994.

/3/ Spliid, H., Procedure and analysis of data for proficiency tests and environmental

analyses, Report to Danish Environmental Protection Agency, 1994 (in Danish). /4/ Eurofins A/S, Schedule for a proficiency test, document may be downloaded from

www.eurofins.dk/proficiencytest. /5/ Ministry of Environment regulation no. 900 on quality criteria for environmental

measurements, 19 August 2011 (in Danish). /6/ ISO 13528, Statistical methods for use in proficiency testing by interlaboratory

comparison, 2005. /7/ NYT fra REFLAB 2009-3: Organisk stof, næringsstoffer, suspenderet stof, chlo-

rid, sulfat og konduktivitet i spildevand, 2009.

www.eurofins.dk/proficiencytest

A P P E N D I C E S

A P P E N D I X A

List of participants

A-1

Laboratory Town Country Analyseenheden Tjele Danmark

AquaDjurs - Fornæs Renseanlæg Grenaa Danmark

Bjergmarken R/A, Roskilde Forsyning Roskilde Danmark

CP Kelco ApS, Spildevandslaboratoriet Ll. Skensved Danmark

Dianalund Renseanlæg Dianalund Danmark

Eurofins Miljø A/S Vejen Danmark

Faxe Spildevand Faxe Danmark

Faxe Spildevand Faxe Danmark

Fredericia Spildevand A/S Fredericia Danmark

Greve Solrød Forsyning Greve Danmark

Hach Lange ApS Brønshøj Danmark

Halsnæs Kommunale Forsyning A/S Liseleje Danmark

Hedensted Spildevand A/S Daugård Danmark

Hedensted Spildevand A/S Daugård Danmark

Holstebro Centralrenseanlæg, Vestforsyning A/S Holstebro Danmark

Ikast-Brande Spildevand Ikast Danmark

Kerteminde Forsyning - Spildevand A/S Kerteminde Danmark

Kolding Spildevand A/S Bjert Danmark

Lynettefællesskabet I/S København K Danmark

Mølleåværkets Driftslaboratorium Lyngby Danmark

Måløv Renseanlæg Måløv Danmark

Nyborg Renseanlæg Nyborg Danmark

Næstved Centralrenseanlæg Næstved Danmark

Provas Haderslev Forsyningsservice Haderslev Danmark

Randers Spildevand A/S Randers NØ Danmark

Rensningsanlæg Øst, Esbjerg Esbjerg Danmark

Rensningsanlæg Øst, Esbjerg, Spildevandslaborato-riet Esbjerg Danmark

Ringkøbing-Skjern Forsyning A/S, Spildevand Skjern Danmark

Ringsted Renseanlæg Ringsted Danmark

Rønne Renseanlæg Rønne Danmark

SK Forsyning, Slagelse Renseanlæg Slagelse Danmark




Sun Chemicals, E30 Køge Danmark

A-2

Svendborg Centralrenseanlæg Skårup Fyn Danmark

Sønderborg Renseanlæg Sønderborg Danmark

Vandsamarbejdet A/S Holstebro Danmark

Vejen Renseanlæg Vejen Danmark

Vejle Spildevand A/S Vejle Danmark

Århus Universitet Silkeborg Danmark

Heilsufrødiliga starvsstovan Tórshavn Færøerne

Eurofins Environment Testing Norway, avd. Bergen Bergen Norge

Eurofins Norsk Miljøanalyse, avd. Moss Moss Norge

LabNett Hamar Hamar Norge

Norges Geotekniske Institutt Oslo Norge

Hallsta Pappersbruk Hallstavik Sverige

Holmen Paper Norrköping Sverige

Preem AB Göteborg Göteborg Sverige

Rottneros Bruk AB Rottneros Sverige

Smurfit Kappa Kraftliner Piteå Sverige

St1 Refinery AB Göteborg Sverige

Södra Cell AB Mönsterås Mönsterås Sverige

Trollhättan Energi AB, Arvidstorps Lab. Trollhättan Sverige

Yara AB Köping Sverige

Eksjö Kommunala Laboratorium Eksjö Sverige

GRYAAB AB Göteborg Sverige

Kalmar Vatten AB, VA-lab, Avloppsreningsverket Kalmar Sverige

Klippans Reningsverk Klippan Sverige

Laboratoriet vid Smedjeholms Arv Falkenberg Sverige

Mjölby Kommun Mjölby Sverige

Motala Kommun Motala Sverige

NSVA/Öresundsverket Helsingborg Sverige

Uddebo Laboratorium Luleå Sverige

VIVAB Varberg Sverige

A P P E N D I X B

Sample preparation

B-1

Stock solution Prepared from Concentration Stock TN 3.000 g Disodium edetate, 2H2O

milli-Q water up to 1000.0 g TN: 225.8 mg/kg N

Stock NH4 1.000 g Ammonium chloride (NH4Cl) milli-Q water up to 1000.1 g

NH4: 261.9 mg/kg N

Stock NO3 2.500 g Potassium nitrate (KNO3) milli-Q water up to 1000.0 g

NO3: 346.4 mg/kg N

Stock NaCl 50.000 g Sodium chloride (NaCl) milli-Q water up to 1000.0 g

conductivity: c. 10680 mS/m

Sample Sample prepared from TN mg/L N

NH4 mg/L N

NO3 mg/L N

Conductivity mS/m

A1 20.00 g stock NH4 25.00 g stock NO3 25.00 g stock TN 45.00 g stock NaCl Sample B1 up to 34.00 kg

0.997· 4.088

+ 0.575

0.997· 1.007

+ 0.154

0.997· 1.865

+ 0.255

0.997· c. 115

+ c. 14

B1 250.00 g stock NH4 350.00 g stock NO3 350.00 g stock TN 700.00 g stock NaCl Sample B1 up to 65.00 kg

4.088 1.007 1.865 c. 115

Sample Sample prepared from pH

A2/B2 17.00 g Potassium dihydrogen phosphate (KH2PO4)

70.98 g Disodium hydrogen phos-phate (Na2HPO4)

milli-Q water up to 12500 g

c. 7.4

A P P E N D I X C

Control of spike value

C-1

Total nitrogen, mg/L N Control of differences within sample pairs

Laboratory Difference AB

1 -0.000 2 -0.160 3 -0.060 4 0.020 5 2.180 UC 6 -0.010 7 0.080 8 -0.110 9 0.015

10 -0.000 11 0.310 12 0.140 13 -0.260 14 0.240 15 -0.040 16 -0.080 17 0.140 18 0.100 19 -0.147 20 -0.310 21 -0.840 22 -0.000 23 -0.040 24 0.160 25 0.010 26 0.000 27 0.050 28 -0.110 29 -0.200 30 -0.070

31A 0.080 31B -0.710

32 -0.840 33 -0.470 34 -0.510 35 0.010 36 -0.040 37 -0.020 38 -0.030 39 0.080 40 -0.010 41 0.260 42 -0.067 43 0.060 UG 44 0.340 45 -0.394 46 - 47 0.000 48 -0.150 49 -0.210 50 -0.035 51 -0.040 52 -0.530 UG 53 -0.160 54 -0.086 55 -

56 0.000 57 -0.102 58 0.020 59 -0.020 60 0.130 61 -0.130 62 -0.050 63 0.160 64 0.030 65 -0.020

No of labs., p 61 No of repl., n 2

d -0.068 s² 0.053 s 0.230

t = √p · (d/s) -2.3113 Sign. level, p(t) 0.0243 * * denotes that there is a significant differ-ence (t-test, 5%-level) ** denotes that there is a significant differ-ence (t-test, 1%-level) *** denotes that there is a significant differ-ence (t-test, 0.1%-level) UC denotes a Cochran outlier UG denotes a Grubbs outlier .

C-2

Ammonium, mg/L N Control of differences within sample pairs


1 -0.010 2 -0.060 3 -0.022 4 -0.010 5 0.010 6 0.002 7 -0.010 8 0.030 9 -0.175 UC

10 0.000 11 -0.010 12 0.010 13 -0.020 14 -0.010 15 0.000 16 -0.010 17 -0.000 18 -0.001 19 -0.002 20 -0.010 21 0.000 22 -0.010 23 -0.030 24 -0.000 25 0.022 26 -0.000 27 -0.010 28 0.010 29 0.207 UC 30 0.020

31A -0.020 31B 0.050 UG

32 0.050 UG 33 0.090 UG 34 0.030 UG 35 0.000 36 0.000 37 -0.010 38 -0.013 39 0.000 40 0.010 41 0.394 UC 42 0.087 43 0.060 44 0.050 45 0.001 46 - 47 - 48 0.000 49 - 50 - 51 - 52 -0.010 53 - 54 0.004 55 0.000

56 0.070 57 -0.006 58 0.000 59 -0.005 60 -0.010 61 0.000 62 0.050 63 0.000 64 - 65 -0.009


d 0.002 s² 0.001 s 0.024

t = √p · (d/s) 0.7287 Sign. level, p(t) 0.4695 No test statistics were found to be signifi-cant UC denotes a Cochran outlier UG denotes a Grubbs outlier

C-3

Nitrit+nitrat, mg/L N Control of differences within sample pairs


1 -0.000 2 -0.220 UC 3 0.000 4 0.000 5 -0.020 6 -0.005 7 -0.050 8 0.010 9 -0.060

10 -0.050 11 -0.050 12 -0.040 13 -0.030 14 -0.060 15 -0.020 16 0.000 17 -0.010 18 -0.060 19 -0.004 20 0.010 21 0.010 22 -0.020 23 -0.080 24 -0.030 25 -0.050 26 -0.020 27 -0.020 28 -0.030 29 0.050 30 -0.080

31A -0.080 31B -0.040

32 -0.030 33 -0.070 34 -0.040 35 - 36 0.000 37 -0.040 38 -0.000 39 -0.030 40 -0.140 41 0.009 42 -0.011 43 0.070 44 0.050 45 0.001 46 - 47 - 48 -0.010 49 - 50 - 51 - 52 0.010 53 - 54 -0.003 55 0.010

56 -0.010 57 -0.027 58 - 59 -0.020 60 - 61 - 62 0.020 63 -0.060 64 0.010 65 -


d -0.021 s² 0.001 s 0.036

t = √p · (d/s) -4.2836 Sign. level, p(t) 0.0001 *** * denotes that there is a significant differ-ence (t-test, 5%-level) ** denotes that there is a significant differ-ence (t-test, 1%-level) *** denotes that there is a significant differ-ence (t-test, 0.1%-level) UC denotes a Cochran outlier Difference for sample pair AB is significant-ly different from 0, and data should be corrected with the dif-ference (in spike value), during execution of Cochran's test.

C-4

Konduktivitet, mS/m Control of differences within sample pairs


1 - 2 0.70 3 - 4 - 5 - 6 -0.20 7 15.10 UG 8 0.00 9 -

10 - 11 -9.90 12 - 13 -0.90 14 0.10 15 - 16 - 17 - 18 - 19 - 20 -11.90 21 - 22 - 23 - 24 -0.70 25 - 26 - 27 - 28 - 29 - 30 -

31A - 31B -

32 - 33 - 34 - 35 2.10 36 - 37 - 38 0.10 39 - 40 - 41 1.10 42 -0.10 43 -1.55 UG 44 0.10 45 -0.20 46 0.50 47 0.50 48 -0.00 49 - 50 - 51 - 52 -0.80 53 0.10 54 -0.50 55 -0.30

56 -0.20 57 -12.77 UG 58 0.30 59 - 60 0.20 61 0.10 62 0.10 63 0.10 64 - 65 0.60


d -0.68 s² 8.75 s 2.96

t = √p · (d/s) -1.2137 Sign. level, p(t) 0.2354 No test statistics were found to be signifi-cant UG denotes a Grubbs outlier

C-5

pH, Control of differences within sample pairs


1 - 2 0.020 3 -0.010 4 0.020 5 - 6 -0.080 UC 7 0.140 UC 8 0.020 9 0.000

10 0.010 11 0.010 12 0.000 UG 13 -0.030 14 -0.060 UC 15 -0.004 UG 16 - 17 -0.020 18 0.000 19 0.000 20 -0.020 21 0.010 22 0.000 23 0.000 24 0.000 25 0.000 26 -0.010 27 -0.020 28 -0.033 29 0.000 30 0.010

31A - 31B 0.050 UG

32 0.020 33 -0.100 UC 34 0.020 35 0.000 36 -0.010 37 - 38 0.005 39 0.000 40 0.000 41 0.010 42 0.000 43 0.000 44 0.000 45 0.000 46 -0.010 47 0.000 48 0.010 49 -0.073 UC 50 0.000 51 - 52 0.000 53 0.010 54 0.000 55 -0.010

56 0.000 57 0.000 58 -0.020 59 0.010 60 0.000 61 0.030 62 0.020 63 0.000 64 - 65 0.000


d 0.001 s² 0.000 s 0.013

t = √p · (d/s) 0.4598 Sign. level, p(t) 0.6476 No test statistics were found to be signifi-cant UC denotes a Cochran outlier UG denotes a Grubbs outlier

A P P E N D I X D

Control of recovery

D-1

Total nitrogen, mg/L N Control of recovery, average of results

Laboratory Sample pair AB

1 4.210 2 4.000 3 3.830 4 4.040 5 5.270 UC 6 3.885 7 4.210 8 4.235 9 3.923

10 4.200 11 4.035 12 4.330 13 4.160 14 4.200 15 3.890 16 4.270 17 3.780 18 3.900 19 4.383 20 3.845 21 3.640 22 3.950 23 3.860 24 3.890 25 3.975 26 4.180 27 4.165 28 4.055 29 3.540 30 3.755

31A 4.350 31B 4.145

32 4.080 33 4.065 34 4.055 35 4.155 36 4.450 37 3.910 38 3.750 39 3.900 40 3.935 41 3.780 42 4.153 43 4.910 UG 44 3.470 45 4.185 46 - 47 3.820 48 3.585 49 3.855 50 3.907 51 4.110 52 5.155 UG 53 3.820 54 4.301 55 -

56 3.860 57 3.970 58 3.980 59 4.010 60 4.165 61 3.765 62 4.125 63 4.310 64 3.565 65 3.970


m 3.997 s² 0.048 s 0.218

Assigned value, µ 4.09 Recovery, % 97.7 t = √p · (m-µ)/s -3.3203 Sign. level, p(t) 0.0015 ** * denotes that there is a significant differ-ence (t-test, 5%-level) ** denotes that there is a significant differ-ence (t-test, 1%-level) *** denotes that there is a significant differ-ence (t-test, 0.1%-level) UC denotes a Cochran outlier UG denotes a Grubbs outlier

D-2

Ammonium, mg/L N Control of recovery, average of results


1 1.005 2 1.070 3 0.921 4 0.995 5 1.035 6 1.035 7 1.025 8 1.025 9 1.083 UC

10 1.010 11 1.055 12 1.015 13 1.010 14 1.005 15 1.030 16 1.015 17 1.000 18 0.980 19 1.084 20 1.075 21 1.010 22 1.015 23 0.945 24 1.000 25 0.949 26 1.000 27 0.995 28 1.035 29 1.097 UC 30 1.010

31A 1.000 31B 1.335 UG

32 1.365 UG 33 1.335 UG 34 1.325 UG 35 1.010 36 1.060 37 0.985 38 0.938 39 1.050 40 1.045 41 1.220 UC 42 1.032 43 0.920 44 1.025 45 1.057 46 - 47 - 48 1.030 49 - 50 - 51 - 52 1.005 53 - 54 1.046 55 1.040

56 1.085 57 1.006 58 1.040 59 0.992 60 1.015 61 1.010 62 1.065 63 1.020 64 - 65 0.994


m 1.016 s² 0.001 s 0.037

Assigned value, µ 1.01 Recovery, % 100.6 t = √p · (m-µ)/s 1.1303 Sign. level, p(t) 0.2636 No test statistics were found to be signifi-cant UC denotes a Cochran outlier UG denotes a Grubbs outlier

D-3

Nitrit+nitrat, mg/L N Control of recovery, average of results


1 1.800 2 1.560 UC 3 1.640 4 1.870 5 1.770 6 1.862 7 1.535 8 1.515 9 1.680

10 1.715 11 1.795 12 1.700 13 1.555 14 1.560 15 1.630 16 1.700 17 1.625 18 1.610 19 2.016 20 1.865 21 1.525 22 1.660 23 1.670 24 1.765 25 1.675 26 1.770 27 1.770 28 1.715 29 1.535 30 1.680

31A 1.590 31B 1.700

32 1.745 33 1.775 34 1.700 35 - 36 1.790 37 1.760 38 1.760 39 1.725 40 1.730 41 1.825 42 1.970 43 2.135 44 1.725 45 1.799 46 - 47 - 48 1.795 49 - 50 - 51 - 52 1.725 53 - 54 1.824 55 1.885

56 1.815 57 1.801 58 - 59 1.790 60 - 61 - 62 1.810 63 1.660 64 1.925 65 -


m 1.740 s² 0.015 s 0.123

Assigned value, µ 1.87 Recovery, % 93.1 t = √p · (m-µ)/s -7.7706 Sign. level, p(t) 0.0000 *** * denotes that there is a significant differ-ence (t-test, 5%-level) ** denotes that there is a significant differ-ence (t-test, 1%-level) *** denotes that there is a significant differ-ence (t-test, 0.1%-level) UC denotes a Cochran outlier

D-4

Konduktivitet, mS/m Control of recovery, average of results


1 - 2 115.65 3 - 4 - 5 - 6 110.70 7 242.55 UG 8 111.50 9 -

10 - 11 117.55 12 - 13 110.55 14 112.05 15 - 16 - 17 - 18 - 19 - 20 119.05 21 - 22 - 23 - 24 104.65 25 - 26 - 27 - 28 - 29 - 30 -

31A - 31B -

32 - 33 - 34 - 35 114.05 36 - 37 - 38 111.75 39 - 40 - 41 113.15 42 112.25 43 99.17 UG 44 112.05 45 110.80 46 111.95 47 111.45 48 111.90 49 - 50 - 51 - 52 106.85 53 111.05 54 109.25 55 111.45

56 111.00 57 -5.28 UG 58 110.65 59 - 60 112.80 61 111.25 62 110.15 63 111.95 64 - 65 111.00


m 111.73 s² 7.44 s 2.73

Assigned value, µ 111.5 Recovery, % 100.2 t = √p · (m-µ)/s 0.4467 Sign. level, p(t) 0.6586 No test statistics were found to be signifi-cant UG denotes a Grubbs outlier

D-5

pH, Control of recovery, average of results


1 - 2 7.550 3 7.505 4 7.440 5 - 6 7.490 UC 7 7.580 UC 8 7.490 9 7.540

10 7.445 11 7.445 12 7.260 UG 13 7.545 14 7.500 UC 15 7.276 UG 16 - 17 7.470 18 7.480 19 7.460 20 7.410 21 7.465 22 7.510 23 7.420 24 7.440 25 7.500 26 7.435 27 7.430 28 7.438 29 7.450 30 7.445

31A - 31B 7.205 UG

32 7.460 33 7.350 UC 34 7.460 35 7.500 36 7.445 37 - 38 7.425 39 7.510 40 7.440 41 7.465 42 7.510 43 7.470 44 7.500 45 7.480 46 7.465 47 7.450 48 7.455 49 7.510 UC 50 7.400 51 - 52 7.460 53 7.475 54 7.440 55 7.465

56 7.480 57 7.440 58 7.450 59 7.445 60 7.460 61 7.475 62 7.460 63 7.500 64 - 65 7.450


m 7.466 s² 0.001 s 0.033

Assigned value, µ 7.46 Recovery, % 100.1 t = √p · (m-µ)/s 1.2344 Sign. level, p(t) 0.2228 No test statistics were found to be signifi-cant UC denotes a Cochran outlier UG denotes a Grubbs outlier

A P P E N D I X E

Concentration level

E-1

Concentration level

Parameter Unit Sample Bottle no. I II Bottle Sample AssignedAverage Average value Measured Assigned

Total nitrogen mg/L N A1 4,37 4,66 4,52 4,52 4,65 0,62 0,564,39

B1 4,00 3,92 3,96 3,90 4,093,84 3,84

Ammonium mg/L N A1 1,180 1,180 1,170 1,16 0,155 0,151,160 1,160

B1 1,020 1,020 1,015 1,011,010 1,010

Nitrite+nitrate mg/L N A1 1,95 1,95 1,96 2,12 0,22 0,251,97 1,97

B1 1,74 1,74 1,74 1,871,74 1,74

pH A2 7,51 7,51 7,52 7,46 -0,01 07,52 7,52

B2 7,52 7,52 7,53 7,467,53 7,53

SPIL-2 (2012)

Spike

A P P E N D I X F

Homogeneity and stability

F-1

PT: SPIL-2 2012Ammonium

Unit: mg/L NSigma: 0,075 6.5% of level Responsible for tests: agk/kms

6.5% of level or 1.3*ST max

Homogeneity test Date: Stability test Date:

Sample x(a) x(b) average sd sd^2 Sample x(a) x(b)A1 1,14 1,14 1,14 0,000 0,000 1,18A8 1,13 1,16 1,15 0,021 0,000 1,16A16 1,14 1,16 1,15 0,014 0,000A24 1,15 1,15 1,15 0,000 0,000A32 1,14 1,15 1,15 0,007 0,000A40 1,14 1,15 1,15 0,007 0,000 For stabilityA48 1,14 1,15 1,15 0,007 0,000 General average (y): 1,17A56 1,14 1,15 1,15 0,007 0,000 /x-y/ = 0,023A64 1,14 1,16 1,15 0,014 0,000A72 1,14 1,16 1,15 0,014 0,000A80 1,15 1,15 1,15 0,000 0,000A88 1,15 1,15 1,15 0,000 0,000 Conclusions

ss = 0 0.3*sigma= 0,022For homogeneity /x-y/ = 0,023General average (x) 1,15 Analytical Is sw < 0,15*sigmaSample average sd (sx) 0,003 quality YESWithin-sample sd (sw): 0,010Between-samples sd (ss): 0 Homogeneity:SL in the Proficiency Test: 0,035 YESSR in the Proficiency Test: 0,039

Stability:NO

Parameter:

Is ss < 0.3*sigma?

/x-y/ < 0.3*sigma?

2012-05-09 2012-05-24

F-2

PT: SPIL-2 2012Nitrate

Unit: mg/L NSigma: 0,1257 6.5% of level Responsible for tests: agk/kms



Sample x(a) x(b) average sd sd^2 Sample x(a) x(b)A1 1,97 1,90 1,94 0,049 0,002 1,95A8 1,91 1,95 1,93 0,028 0,00 1,97A16 1,80 1,96 1,88 0,113 0,013A24 1,97 1,93 1,95 0,028 0,001A32 1,87 1,93 1,90 0,042 0,002A40 1,94 1,92 1,93 0,014 0,000 For stabilityA48 1,95 1,96 1,96 0,007 0,000 General average (y): 1,96A56 1,95 1,93 1,94 0,014 0,000 /x-y/ = 0,026A64 1,95 1,95 1,95 0,000 0,000A72 1,95 1,95 1,95 0,000 0,000A80 1,94 1,96 1,95 0,014 0,000A88 1,93 1,95 1,94 0,014 0,000 Conclusions

ss = 0 0.3*sigma= 0,038For homogeneity /x-y/ = 0,026General average (x) 1,93 Analytical Is sw < 0,15*sigmaSample average sd (sx) 0,023 quality NOWithin-sample sd (sw): 0,040Between-samples sd (ss): 0 Homogeneity:SL in the Proficiency Test: 0,121 YESSR in the Proficiency Test: 0,124

Stability:YES

Parameter:

Is ss < 0.3*sigma?

/x-y/ < 0.3*sigma?

2012-05-09 2012-05-24

F-3

PT: SPIL-2 2012pH

Unit:Sigma: 0,065 1,3*sT max Responsible for tests: agk/kms



Sample x(a) x(b) average sd sd^2 Sample x(a) x(b)A1 7,48 7,49 7,49 0,007 0,000A9 7,48 7,49 7,49 0,007 0,00A18 7,48 7,49 7,49 0,007 0,000A27 7,48 7,49 7,49 0,007 0,000A36 7,48 7,49 7,49 0,007 0,000A45 7,48 7,49 7,49 0,007 0,000 For stabilityA54 7,48 7,49 7,49 0,007 0,000 General average (y):A63 7,48 7,49 7,49 0,007 0,000 /x-y/ =A72 7,48 7,49 7,49 0,007 0,000A81 7,48 7,49 7,49 0,007 0,000A90 7,48 7,48 7,48 0,000 0,000A98 7,49 7,49 7,49 0,000 0,000 Conclusions

ss = 0 0.3*sigma= 0,020For homogeneity /x-y/ =General average (x) 7,49 Analytical Is sw < 0,15*sigmaSample average sd (sx) 0,002 quality YESWithin-sample sd (sw): 0,006Between-samples sd (ss): 0 Homogeneity:SL in the Proficiency Test: 0,032 YESSR in the Proficiency Test: 0,033

Stability:No data

Parameter:

2012-05-09

Is ss < 0.3*sigma?

/x-y/ < 0.3*sigma?

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