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Quality Documentation
January 2015
Proficiency test SPIL-4 (2014) Nitrogen parameters in wastewater (effluent)
Proficiency test SPIL-4 (2014) Quality Documentation January 2015
Eurofins Miljø A/S Smedeskovvej 38 DK-8464 Galten Denmark Tlf: +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-4 (2014)
Project No
20404-44
Authors
Maj-Britt Fruekilde
Date 2015-01-28
Approved by Stine Ottsen
Quality Documentation Report
20150129
Revision Description By Approved Date
Key words Analytical quality, assigned value, precision, trueness, homogeneity, stability, total nitrogen, ammonium, nitrite+nitrate, conductivity, pH, wastewater
Classification
Open
Internal
Proprietary
Distribution
DANAK Eurofins:
Maj-Britt Fruekilde, Stine Ottsen
CONTENTS
1 INTRODUCTION ........................................................................................................... 1
2 FEATURES OF THE PROFICIENCY TEST .................................................................. 2
2.1 Sample preparation ....................................................................................................... 2
2.2 Statistical analysis of participants’ data ......................................................................... 2
2.3 Assigned and spike value .............................................................................................. 2
2.3.1 Assigned and spike values ............................................................................................ 3
2.3.2 Test of spike values ...................................................................................................... 3
2.3.3 Test of assigned values ................................................................................................. 3
3 HOMOGENEITY OF SAMPLES .................................................................................... 4
4 CONCLUSION .............................................................................................................. 5
5 REFERENCES ............................................................................................................. 6
ANNEX A LIST OF PARTICIPANTS ..................................................................................... 8
ANNEX B SAMPLE PREPARATION .................................................................................. 11
ANNEX C CONTROL OF SPIKE VALUES ......................................................................... 12
ANNEX D CONTROL OF RECOVERY ............................................................................... 17
ANNEX E CONCENTRATION LEVEL ................................................................................ 22
ANNEX F HOMOGENEITY AND STABILITY ..................................................................... 23
1
1 INTRODUCTION
A proficiency test on the analysis of nitrogen parameters in wastewater was conducted on 13 November 2014. 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 /1/ on 15 De-cember 2014.
2
2 FEATURES OF THE PROFICIENCY TEST
Participants in the proficiency test were a total of 67 laboratories from Denmark, Nor-way and Sweden. A list of participants is shown in Appendix A.
The closing date for submission of results was 1 December 2014. All participants ex-cept laboratory no 32 and 55 had submitted 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 effluent. Sample preparation is described 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 effluent. The table also gives the expanded uncertainty of the assigned values.
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 6.9 0.13 1.7 ammonium NH4 mg/L N 0.1-2 1.40 0.014 0.18 nitrite+nitrate NO2+3 mg/L N 1-5 2.50 0.031 0.59 conductivity γ25 mS/m 50-300 116.0 0.54 0.1 pH pH 6-9 7.27 0.052 0
3
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.
In order to ensure optimal use of the data, the assigned value is calculated as the av-erage of the median for both samples in the sample pair after subtraction of the spike value. The spike values are calculated from sample preparation except for γ25 where the spike value is the difference between median values for the two samples in the sample pair.
The assigned value for TN is operationally defined and is a consensus value based upon the median for method no. 1, 2, 3 and 7. A list of method identification numbers is found in the report to participants /1/. Assigned values for NH4, NO2+3, conductivity and pH are consensus values for all laboratories based on the median.
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.
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 and the control of assigned value at Eurofins confirmed the value (Appendix E).
4
3 HOMOGENEITY OF SAMPLES
The homogeneity of samples was tested using the following parameters as indicators:
NH4 Homogeneity test
NO2+3 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)
Homogeneity is evaluated by comparing the between bottle variance to 0.3 * the standard deviation for evaluation of participants’ performance (0.3 ∙ σ�) specified by the Danish EPA /5/. This test ensures that heterogeneity 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 homogeneity show that the samples are homogeneous.
5
4 CONCLUSION
The quality control performed, including test of sample homogeneity as well as test of recovery of spike and assigned values, shows that the samples and their assigned val-ues are suitable for testing the proficiency of the participating laboratories for all pa-rameters. The results are also suitable for estimation of the general quality of analyses among all participating laboratories.
6
5 REFERENCES
/1/ Eurofins A/S, Proficiency test SPIL-4 (2014), Report to participants, December 2014.
/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. 231 on quality criteria for environmental measurements, 5 March 2014 (in Danish).
/6/ ISO 13528, Statistical methods for use in proficiency testing by interlaboratory comparison, 2005.
7
A N N E X E S
8
ANNEX A LIST OF PARTICIPANTS
Laboratory Town Country
Eurofins Miljø A/S Vejen Denmark
Højmarklaboratoriet Lem St. Denmark
FORCE LabVest Holstebro Denmark
CP Kelco ApS, Spildevandslaboratoriet Ll. Skensved Denmark
AquaDjurs - Fornæs Renseanlæg Grenaa Denmark
Bjergmarken R/A, Roskilde Forsyning Roskilde Denmark
Faxe Forsyning Faxe Denmark
Faxe Forsyning Faxe Denmark
Greve Solrød Forsyning Greve Denmark
Halsnæs Kommunale Forsyning A/S Liseleje Denmark
Hedensted Spildevand A/S Daugård Denmark
Hedensted Spildevand A/S Daugård Denmark
Hillerød Forsyning Spildevand A/S Hillerød Denmark
Holstebro Centralrenseanlæg, Vestforsyning A/S Holstebro Denmark
Kerteminde Forsyning - Spildevand A/S Kerteminde Denmark
Kolding Spildevand A/S Bjert Denmark
Køge-Egnens Renseanlæg Køge Denmark
Biofos A/S København K Denmark
Mølleåværkets Driftslaboratorium Lyngby Denmark
Nyborg Renseanlæg Nyborg Denmark
Næstved Centralrenseanlæg Næstved Denmark
Provas Haderslev Forsyningsservice A/S Haderslev Denmark
Randers Spildevand A/S Randers SØ Denmark
Esbjerg Forsyning Spildevandslaboratorium Esbjerg Denmark
9
Laboratory Town Country
Esbjerg Forsyning Spildevandslaboratorium Esbjerg Denmark
Ringkøbing-Skjern Forsyning A/S, Spildevand Skjern Denmark
Ringsted Renseanlæg Ringsted Denmark
Rønne Renseanlæg Rønne Denmark
SK Forsyning, Slagelse Renseanlæg Slagelse Denmark
SK Forsyning, Slagelse Renseanlæg Slagelse Denmark
SK Forsyning, Slagelse Renseanlæg Slagelse Denmark
SK Forsyning, Slagelse Renseanlæg Slagelse Denmark
SK Forsyning, Slagelse Renseanlæg Slagelse Denmark
Svendborg Centralrenseanlæg Skårup Fyn Denmark
Sønderborg Forsyning Sønderborg Denmark
Vandrens - Stigsnæs Industripark A/S Skælskør Denmark
Vejen Renseanlæg Vejen Denmark
Vejle Spildevand A/S Vejle Denmark
Middelfart Spildevand A/S Middelfart Denmark
Eurofins Environment Testing Norway AS Moss Norway
Norways Geotekniske Institutt Oslo Norway
Eurofins Environment Testing Sweden AB Lidköping Sweden
Arctic Paper Munkedals AB Munkedal Sweden
Holmen Paper Norrköping Sweden
Preem AB Göteborg Göteborg Sweden
Preemraff Lysekil Lysekil Sweden
Smurfit Kappa Kraftliner Piteå Sweden
St1 Refinery AB Göteborg Sweden
Södra Cell AB, Värö Väröbacka Sweden
10
Laboratory Town Country
Yara AB Köping Sweden
Ernemar Laboratoriet Oskarshamn Sweden
GRYAAB AB Göteborg Sweden
Kalmar Vatten AB, VA-lab, Avloppsreningsverket Kalmar Sweden
Kristianstad Kommun Kristianstad Sweden
Käppalaverket Lidingö Sweden
Mjölby Kommun Mjölby Sweden
Motala Kommun Motala Sweden
NSVA/Öresundsverket Helsingborg Sweden
Nynäshamn Kommun, VA-avdelningen Nynäshamn Sweden
Tekniska förvaltningen, Verksamhetsstöd VA, Labo-ratoriet Örebro Sweden
VA SYD Klaghamns Avloppsreningsverket Malmö Sweden
VA SYD Källby Avloppsreningsverk Malmö Sweden
VA SYD Sjölundalaboratoriet Malmö Sweden
VA-SYD, Ellingelaboratoriet Malmö Sweden
VETAB Laboratoriet Vetlanda Sweden
Västerviks Miljö & Energi AB, Vattenlaboratoriet Västervik Sweden
Vallviks Bruk AB Vallvik Sweden
11
ANNEX B SAMPLE PREPARATION
Stock solution Prepared from Concentration Stock TN 3.0001 g Disodium edetate, 2H2O
milli-Q water up to 1000.0 g TN: 225.8 mg/kg N
Stock NH4 1. 0001 g Ammonium chloride (NH4Cl) milli-Q water up to 1000.0 g
NH4: 261.9 mg/kg N
Stock NO3 2.5002 g Potassium nitrate (KNO3) milli-Q water up to 1000.0 g
NO3: 346.4 mg/kg N
Sample Sample prepared from TN
mg/L N NH4 mg/L N
NO3
mg/L N Conductivity mS/m
A1 25.03 g stock NH4 60.04 g stock NO3 150.04 g stock TN Sample B1 up to 35.00 kg
0.993· (c+3.64)
+ 1.75
0.993· (a+0.561)
+ 0.187
0.993· (b+0.495)
+ 0.594
e
B1 150.00 g stock NH4 100.00 g stock NO3 800.00 g stock TN Filtered effluent water from Esbjerg Vest waste water treatment plant up to 70.00 kg
c+3.64 a+0.561 b+0.495 d
Sample Sample prepared from pH A2/B2 Filtered effluent water from Esbjerg
Vest waste water treatment plant f
12
ANNEX C CONTROL OF SPIKE VALUES
Total nitrogen, mg/L N Control of differences within sample pairs
Laboratory Difference AB
1 -0.300 2A -0.300
3 -0.860 UG 4 -0.340 5 -0.140 6 -0.270 7 0.110
8A 0.030 8B -0.150 8C -0.010
9 0.010 10 -0.150 11 0.440 12 -0.400 13 -0.100 14 -0.210 15 -0.310 16 0.980 17 0.070 18 0.090 19 0.190
20A 0.330 20B -
21 0.020 22 -0.070 23 -0.010 24 -0.050 25 0.020 26 0.020 27 0.150 28 -0.020 29 -0.100 30 0.020 31 -0.420 33 -0.040 34 -0.260 35 -0.060 36 -0.600
37A -0.110 37B -0.020
38 -0.100 39 -0.030 40 -0.057 41 0.040 42 -0.470 43 0.010 44 -0.440 UG 45 -0.680 46 0.030 47 0.130 48 0.480
49 0.060 50 - 51 0.180 52 -0.240 53 -0.130 54 -0.300 56 -0.450 57 -0.200
58A - 58B -
59 - 60 0.190
61A -0.000 61B -0.110 UG
62 -0.060 63 0.010 64 - 65 0.140 66 0.070 67 -0.230 2B -
No of labs., p 62 No of repl., n 2 d -0.058 s² 0.066 s 0.257 t = √p · (d/s) -1.7615 Sign. level, p(t) 0.0832 No test statistics were found to be significant UG denotes a Grubbs outlier
13
Ammonium, mg/L N Control of differences within sample pairs
Laboratory Difference AB
1 -0.010 2A 0.020
3 0.000 4 0.190 UC 5 -0.010 6 - 7 -
8A -0.010 8B - 8C -
9 -0.012 10 0.040 11 0.010 12 -0.020 13 - 14 0.010 15 0.240 UC 16 0.010 17 -0.180 UC 18 0.010 19 0.010
20A 0.020 20B -0.080
21 -0.040 22 0.020 23 0.010 24 0.010 25 0.010 UG 26 0.660 UC 27 -0.040 28 0.000 29 -0.010 30 -0.020 31 0.010 33 -0.040 34 0.030 35 0.040 36 0.020
37A -0.010 37B 0.000
38 0.010 39 0.036 40 0.005 41 0.020 42 0.020 43 0.010 44 -0.025 45 -0.020 46 -0.010 47 0.000 48 0.010 49 0.000 50 0.010 51 -0.020 52 0.000 53 0.000
54 - 56 -0.110 UC 57 0.020
58A 0.040 58B -
59 - 60 0.000
61A 0.030 61B -0.020
62 -0.090 63 -0.020 64 -0.010 65 0.030 66 0.030 67 - 2B -
No of labs., p 56 No of repl., n 2 d 0.000 s² 0.001 s 0.026 t = √p · (d/s) 0.1239 Sign. level, p(t) 0.9019 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
14
Nitrite+nitrate, mg/L N Control of differences within sample pairs
Laboratory Difference AB
1 -0.023 2A -0.190
3 -0.190 4 0.270 5 - 6 - 7 -
8A -0.010 8B - 8C -
9 -0.012 10 -0.645 UC 11 0.050 12 -0.070 13 - 14 0.160 15 -0.062 16 0.200 17 0.000 18 -0.100 19 -
20A 0.030 20B -
21 -0.020 22 -0.030 23 -0.030 24 - 25 0.110 26 0.070 27 0.040 28 -0.040 29 -0.080 30 -0.180 31 -0.040 33 -0.080 34 -0.020 35 0.020 36 0.010
37A -0.020 37B -0.040
38 -0.010 39 -0.022 40 -0.061 41 0.250 42 0.010 43 -0.060 44 -0.010 45 -0.010 46 -0.080 47 -0.010 48 -0.340 UG 49 0.000 50 -0.080 51 0.000 52 -0.030 53 -0.030
54 - 56 -0.100 57 -
58A -0.030 58B -
59 - 60 -0.070
61A -0.060 61B -0.140
62 -0.030 63 -0.030 64 -0.010 65 -0.070 66 -0.080 67 - 2B -
No of labs., p 55 No of repl., n 2 d -0.019 s² 0.008 s 0.089 t = √p · (d/s) -1.5832 Sign. level, p(t) 0.1192 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
15
Conductivity, mS/m Control of differences within sample pairs
Laboratory Difference AB
1 - 2A -3.10 UC
3 - 4 - 5 - 6 - 7 -
8A - 8B - 8C -
9 -0.10 10 - 11 - 12 2.90 UC 13 - 14 - 15 1.17 16 - 17 - 18 - 19 -0.20
20A 0.50 20B -
21 0.90 22 - 23 0.90 24 0.20 25 0.90 26 -0.10 27 0.20 28 - 29 - 30 -0.10 31 - 33 - 34 - 35 0.00 36 -0.20
37A - 37B -
38 - 39 -1.10 40 -0.10 41 0.30 42 - 43 - 44 - 45 -0.10 46 -1.00 47 -0.10 48 -0.20 49 -0.10 UG 50 -0.20 51 -0.10 52 - 53 -
54 -0.20 56 0.90 57 -
58A -0.30 58B -
59 -0.20 60 -
61A - 61B -
62 -0.20 63 -0.40 64 0.20 65 - 66 - 67 - 2B -
No of labs., p 29 No of repl., n 2 d 0.04 s² 0.28 s 0.53 t = √p · (d/s) 0.4462 Sign. level, p(t) 0.6589 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
16
pH, Control of differences within sample pairs
Laboratory Difference AB
1 -0.020 2A -0.050
3 -0.060 4 -0.360 5 -0.050 6 -0.016 7 -
8A -0.050 8B - 8C -
9 -0.100 10 0.130 11 0.400 12 0.300 13 0.090 14 -0.020 15 0.035 16 -0.110 17 -0.040 18 0.000 19 -0.010
20A 0.050 20B -
21 -0.030 22 -0.140 23 -0.300 24 -0.100 25 -0.520
UC 26 0.060 27 0.020 28 -0.060 29 0.000 30 0.010 31 0.060 33 -0.019 34 0.030 35 0.060 36 0.100
37A -
37B 0.050 38 0.290 39 -0.020 40 0.060 41 0.110 42 -0.040 43 -0.030 44 - 45 -0.030 46 0.000 47 0.030 48 0.020 49 0.222 50 0.000 51 0.030 52 0.000 53 -0.030 54 - 56 -0.040 57 0.050
58A 0.050 58B -0.010
59 -0.060 60 -0.040
61A -0.080 61B -
62 -0.010 63 0.010 64 -0.020 65 0.000 66 -0.150 67 - 2B 0.030
No of labs., p 62 No of repl., n 2 d 0.003 s² 0.013 s 0.114 t = √p · (d/s) 0.2253 Sign. level, p(t) 0.8225 No test statistics were found to be significant UC denotes a Cochran outlier
17
ANNEX D CONTROL OF RECOVERY
Total nitrogen, mg/L N Control of recovery, average of results
Laboratory Sample pair AB
1 7.190 2A 6.750
3 5.360 UG 4 7.040 5 6.750 6 6.295 7 7.185
8A 6.945 8B 6.495 8C 7.385
9 7.135 10 6.545 11 6.690 12 6.900 13 7.070 14 7.525 15 7.035 16 6.140 17 7.015 18 7.955 19 7.245
20A 7.445 20B -
21 6.880 22 6.925 23 6.985 24 7.245 25 7.410 26 6.920 27 7.065 28 6.850 29 6.930 30 7.080 31 7.040 33 7.080 34 6.580 35 6.870 36 6.800
37A 7.055 37B 7.310
38 6.740 39 6.735 40 6.935 41 6.500 42 6.715 43 6.835 44 8.970 UG 45 6.740 46 7.005 47 6.925 48 6.750
49 6.620 50 - 51 6.700 52 6.980 53 6.245 54 6.060 56 6.715 57 6.300
58A - 58B -
59 - 60 6.985
61A 7.070 61B 5.385 UG
62 6.540 63 7.025 64 - 65 6.660 66 6.985 67 7.235 2B -
No of labs., p 62 No of repl., n 2 m 6.899 s² 0.113 s 0.337 Assigned value, µ 6.9 Recovery, % 100.0 t = √p · (m-µ)/s -0.0149 Sign. level, p(t) 0.9882 No test statistics were found to be significant UG denotes a Grubbs outlier
18
Ammonium, mg/L N Control of recovery, average of results
Laboratory Sample pair AB
1 1.335 2A 1.410
3 1.270 4 1.325 UC 5 1.345 6 - 7 -
8A 1.325 8B - 8C -
9 1.349 10 1.430 11 1.425 12 1.390 13 - 14 1.535 15 1.532 UC 16 1.375 17 1.530 UC 18 1.445 19 1.365
20A 1.430 20B 1.410
21 1.410 22 1.410 23 1.405 24 1.355 25 1.135 UG 26 1.920 UC 27 1.400 28 1.430 29 1.335 30 1.310 31 1.395 33 1.380 34 1.425 35 1.380 36 1.410
37A 1.375 37B 1.420
38 1.391 39 1.385 40 1.535 41 1.380 42 1.430 43 1.375 44 1.417 45 1.360 46 1.345 47 1.470 48 1.495 49 1.410 50 1.345 51 1.390 52 1.340 53 1.300
54 - 56 1.445 UC 57 1.380
58A 1.500 58B -
59 - 60 1.380
61A 1.425 61B 1.280
62 1.555 63 1.340 64 1.405 65 1.435 66 1.455 67 - 2B -
No of labs., p 56 No of repl., n 2 m 1.396 s² 0.003 s 0.059 Assigned value, µ 1.40 Recovery, % 99.7 t = √p · (m-µ)/s -0.4496 Sign. level, p(t) 0.6548 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
19
Nitrite+nitrate, mg/L N Control of recovery, average of results
Laboratory Sample pair AB
1 2.588 2A 2.405
3 2.295 4 2.265 5 - 6 - 7 -
8A 2.435 8B - 8C -
9 2.431 10 2.277 UC 11 2.525 12 2.385 13 - 14 2.980 15 2.800 16 2.270 17 2.660 18 2.790 19 -
20A 2.535 20B -
21 2.550 22 2.635 23 2.495 24 - 25 2.715 26 2.555 27 2.470 28 2.590 29 2.410 30 2.290 31 2.610 33 2.590 34 2.580 35 2.580 36 2.505
37A 2.420 37B 2.520
38 2.415 39 2.489 40 2.244 41 2.595 42 2.525 43 2.550 44 2.525 45 2.475 46 2.150 47 2.645 48 1.490 UG 49 2.590 50 2.440 51 2.530 52 2.435 53 2.335
54 - 56 2.540 57 -
58A 2.925 58B -
59 - 60 2.365
61A 2.590 61B 2.160
62 2.485 63 2.445 64 2.495 65 2.535 66 2.480 67 - 2B -
No of labs., p 55 No of repl., n 2 m 2.506 s² 0.026 s 0.161 Assigned value, µ 2.50 Recovery, % 100.2 t = √p · (m-µ)/s 0.2880 Sign. level, p(t) 0.7745 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
20
Conductivity, mS/m Control of recovery, average of results
Laboratory Sample pair AB
1 - 2A 110.45 UC
3 - 4 - 5 - 6 - 7 -
8A - 8B - 8C -
9 114.95 10 - 11 - 12 108.45 UC 13 - 14 - 15 110.27 16 - 17 - 18 - 19 116.10
20A 117.35 20B -
21 116.45 22 - 23 118.45 24 117.30 25 115.45 26 115.05 27 118.00 28 - 29 - 30 115.95 31 - 33 - 34 - 35 121.90 36 115.60
37A - 37B -
38 - 39 114.55 40 116.65 41 115.85 42 - 43 - 44 - 45 115.55 46 111.50 47 114.35 48 116.10 49 1169.95 UG 50 115.40 51 116.95 52 - 53 -
54 115.20 56 110.45 57 -
58A 116.55 58B -
59 118.10 60 -
61A - 61B -
62 115.90 63 115.70 64 117.20 65 - 66 - 67 - 2B -
No of labs., p 29 No of repl., n 2 m 115.82 s² 5.27 s 2.30 Assigned value, µ 116.0 Recovery, % 99.8 t = √p · (m-µ)/s -0.4193 Sign. level, p(t) 0.6782 No test statistics were found to be significant UC denotes a Cochran outlier UG denotes a Grubbs outlier
21
pH, Control of recovery, average of results
Laboratory Sample pair AB
1 7.070 2A 7.075
3 7.100 4 7.420 5 7.305 6 7.111 7 -
8A 7.335 8B - 8C -
9 7.400 10 7.205 11 7.100 12 7.250 13 7.425 14 7.030 15 7.502 16 7.205 17 7.050 18 7.500 19 7.255
20A 7.735 20B -
21 7.405 22 7.540 23 7.050 24 7.180 25 6.890 UC 26 7.600 27 7.260 28 7.140 29 7.130 30 7.175 31 7.350 33 7.330 34 7.245 35 7.380 36 7.150
37A - 37B 7.425
38 6.705 39 7.280 40 7.130 41 7.685 42 7.010 43 7.185 44 - 45 7.155 46 7.510 47 7.505 48 7.320 49 7.436 50 7.300 51 7.255 52 7.130 53 7.435
54 - 56 7.120 57 7.355
58A 7.575 58B 7.505
59 7.430 60 7.150
61A 7.160 61B -
62 7.305 63 7.365 64 7.400 65 7.800 66 7.075 67 - 2B 7.135
No of labs., p 62 No of repl., n 2 m 7.288 s² 0.039 s 0.198 Assigned value, µ 7.27 Recovery, % 100.2 t = √p · (m-µ)/s 0.7107 Sign. level, p(t) 0.4800 No test statistics were found to be significant UC denotes a Cochran outlier
22
ANNEX E CONCENTRATION LEVEL
Concentration level SPIL-4 (2014)
Parameter Unit Sample Bottle no. I II Bottle Sample Assigned Spike
Average Average value Measured Assigned
Total nitrogen mg/L N A1 17 8,85 8,87 8,86 8,75 8,6 1,74 1,7
33 8,68 8,53 8,61
54 8,70 8,87 8,79
B1 39 7,00 7,11 7,06 7,01 6,9
46 6,91 7,11 7,01
62 6,82 7,09 6,96
Ammonium mg/L N A1 17 1,500 1,530 1,52 1,527 1,58 0,187 0,18
33 1,530 1,550 1,54
54 1,520 1,530 1,53
B1 39 1,340 1,350 1,35 1,340 1,40
46 1,340 1,340 1,34
62 1,330 1,340 1,34 Nitrite+nitrate mg/L N A1 17 2,70 2,96 2,83 2,91 3,09 0,56 0,59
33 2,96 3,02 2,99
54 2,91 2,92 2,92
B1 39 2,33 2,24 2,29 2,36 2,50
46 2,39 2,39 2,39
62 2,40 2,38 2,39
pH A2 2 7,25 7,30 7,28 7,24 7,27 0,01 0
31 7,20 7,23 7,22
74 7,22 7,22 7,22
B2 2 7,23 7,28 7,26 7,23 7,27
21 7,20 7,22 7,21
54 7,23 7,23 7,23
23
ANNEX F HOMOGENEITY AND STABILITY
PT:SPIL-4 2014
Parameter:NH4
Unit:mg/L P
Sigma:0,1033 6,5% of x Responsible for tests: SMN
6,5% level or 1,3*ST max
Homogeneity test Date:2014-10-28
Sample x(a) x(b) average sd sd^2
8 1,56 1,59 1,6 0,021 0,000
12 1,57 1,60 1,6 0,021 0,00
16 1,56 1,61 1,6 0,035 0,001
18 1,61 1,63 1,6 0,014 0,000
40 1,58 1,61 1,6 0,021 0,000
44 1,57 1,57 1,6 0,000 0,000
49 1,56 1,59 1,6 0,021 0,000
55 1,59 1,59 1,6 0,000 0,000
64 1,57 1,59 1,6 0,014 0,000
74 1,67 1,60 1,6 0,049 0,002
78 1,59 1,58 1,6 0,007 0,000
90 1,58 1,58 1,6 0,000 0,000 Conclusions
ss = 0,011 0.3*sigma=0,03
For homogeneity /x-y/ =
General average (x) 1,59 Analytical Is sw < 0,15*sigma
Sample average sd (sx) 0,019 quality NO
Within-sample sd (sw): 0,022
Between-samples sd (ss): 0,0111 Homogeneity: Is ss < 0.3*sigma?
SL in the Proficiency Test: 0,057 YES
SR in the Proficiency Test: 0,060
24
PT: SPIL-4 2014
Parameter: NO3
Unit: mg/L
Sigma: 0,2 1,3*sT max Responsible for tests: SMN
6,5% level or 1,3*ST max
Homogeneity test Date: 2014-10-28
Sample x(a) x(b) average sd sd^2
8 2,96 3,01 3,0 0,035 0,001
12 3,03 3,13 3,1 0,071 0,005
16 3,02 3,08 3,1 0,042 0,002
18 3,09 3,07 3,1 0,014 0,000
40 2,98 3,00 3,0 0,014 0,000
44 3,07 3,05 3,1 0,014 0,000
49 3,03 2,95 3,0 0,057 0,003
55 3,06 3,06 3,1 0,000 0,000
64 3,08 3,05 3,1 0,021 0,000
74 3,04 2,93 3,0 0,078 0,006
78 2,93 3,05 3,0 0,085 0,007
90 2,99 3,01 3,0 0,014 0,000 Conclusions
ss = 0,02 0.3*sigma= 0,06 For homoge-neity /x-y/ =
General average (x) 3,0 Analytical Is sw < 0,15*sigma
Sample average sd (sx) 0,041 quality NO
Within-sample sd (sw): 0,046
Between-samples sd (ss): 0,024 Homogeneity: Is ss < 0.3*sigma?
SL in the Proficiency Test: 0,154 YES
SR in the Proficiency Test: 0,167
