report 938 waters chem round 186 total kjeldahl nitrogen
TRANSCRIPT
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PTA wishes to gratefully acknowledge the technical assistance provided for this program by Dr M BuckleyProficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.
SD 9.17.10
Waters Proficiency Testing
-
PTA wishes to gratefully acknowledge the technical assistance provided for this program by Dr M Buckley-Smith, GlobaProficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.
PO B
Report No
Waters Proficiency Testing
Round
- Total Kjeldahl Nitrogen, Total Phosphorus
November 2015
PTA wishes to gratefully acknowledge the technical assistance provided for this program by Smith, Global Proficiency Ltd (New
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.
© Copyright
PO Box 7507
Report No
Waters Proficiency Testing
Round
Total Kjeldahl Nitrogen, Total Phosphorus
November 2015
Acknowledgments
PTA wishes to gratefully acknowledge the technical assistance provided for this program by l Proficiency Ltd (New
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.
© Copyright Proficiency Testing Australia
ox 7507 SILVERWATER
Report No
Waters Proficiency Testing
Round No.
Total Kjeldahl Nitrogen, Total Phosphorus
November 2015
Acknowledgments
PTA wishes to gratefully acknowledge the technical assistance provided for this program by l Proficiency Ltd (New
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply
Proficiency Testing Australia
SILVERWATER NSW
Report No . 938
Waters Proficiency Testing
o. 186
Total Kjeldahl Nitrogen, Total Phosphorus
November 2015
Acknowledgments
PTA wishes to gratefully acknowledge the technical assistance provided for this program by l Proficiency Ltd (New Zealand). Also our thanks go to Global
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply
Proficiency Testing Australia
NSW 2128
938
Waters Proficiency Testing
186
Total Kjeldahl Nitrogen, Total Phosphorus -
November 2015
PTA wishes to gratefully acknowledge the technical assistance provided for this program by . Also our thanks go to Global
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply
Proficiency Testing Australia , 2015
2128, Australia
Waters Proficiency Testing
Total Kjeldahl Nitrogen,
PTA wishes to gratefully acknowledge the technical assistance provided for this program by . Also our thanks go to Global
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply
2015
, Australia
PTA wishes to gratefully acknowledge the technical assistance provided for this program by . Also our thanks go to Global
Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply
SD 9.17.10
CONTENTS
1. Foreword ............................................................................................................................ 1
2. Program Features and Design ........................................................................................... 1
3. Statistical Format ............................................................................................................... 2
4. PTA and Technical Adviser’s Comments .......................................................................... 4
5. Outlier Results ................................................................................................................. 25
6. References ...................................................................................................................... 25
APPENDIX A – Results and Data Analysis
Total Kjeldahl Nitrogen .......................................................................................................... A1
Total Phosphorus .................................................................................................................. A7
APPENDIX B – Sample Homogeneity and Stability
Homogeneity and Stability Testing ........................................................................................ B1
APPENDIX C – Documentation
Instructions to Participants .................................................................................................... C1
Method Codes ....................................................................................................................... C3
Results Sheet ........................................................................................................................ C6
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1. Foreword
This report summarises the results of a proficiency testing program on the determination of Total Kjeldahl Nitrogen and Total Phosphorus in waters. This is round 186 in a planned series of programs involving the analysis of chemical and physical parameters of waters. The exercise was conducted in September 2015 by Proficiency Testing Australia (PTA). The main aim of the program was to assess laboratories’ abilities to competently perform the prescribed analyses. The Program Coordinator was Mrs D Mihaila and the Technical Adviser was Dr M Buckley-Smith, Global Proficiency Ltd (New Zealand). This report was authorised by Mrs F Watton, PTA Quality – Business Development Manager.
2. Program Features and Design 2.1 Each laboratory was randomly allocated a unique code number for the program to
ensure confidentiality of results. Reference to each laboratory in this report is by code number only. Please note that a number of laboratories reported more than one set of results and, therefore, their code numbers (with letter) could appear several times in the same data set.
2.2 Laboratories were provided with the "Instructions to Participants" and "Results Sheet"
(see Appendix C). Laboratories were requested to perform the tests according to their routine methods.
2.3 Participants were provided with three plastic vials (labelled PTA 1, PTA 2 and PTA 3)
containing artificial potable water concentrates for testing of Total Kjeldahl Nitrogen and Total Phosphorus.
2.4 A total of 37 laboratories received samples, comprising:
- 30 Australian participants; and
- 7 overseas participants, including:
- China (1), Indonesia (2), Malaysia (1), Namibia (1), New Zealand (1), Romania (1).
Of these 37 laboratories, 4 were unable to submit results by the due date. 2.5 Results (as reported by participants) with corresponding summary statistics (i.e.
number of results, median, normalised interquartile range, uncertainty of the median, robust coefficient of variation, minimum, maximum and range) are presented in Appendix A (for each sample and for each of the analyses performed).
2.6 A robust statistical approach, using z-scores, was utilised to assess laboratories’
testing performance (see Section 3). Robust z-scores and ordered z-score charts relevant to each test are presented in Appendix A.
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The document entitled Guide to Proficiency Testing Australia, 2014 (reference [1]) defines the statistical terms and details the statistical procedures referred to in this report.
2.7 A tabulated listing of laboratories (by code number) identified as having outlier results
can be found on page 25. 2.8 Prior to sample distribution, a number of randomly selected samples were analysed
for homogeneity and stability. Based on the results of this testing (see Appendix B) it was considered that the samples utilised for this program were homogeneous and stable. As such, any results later identified as outliers could not be attributed to any notable sample variability.
3. Statistical Format
For each test the following information is given:
- a table of results and calculated z-scores;
- a list of summary statistics; and
- ordered z-score charts.
3.1 Outlier Results and Z-scores In order to assess laboratories’ testing performance, a robust statistical approach,
using z-scores, was utilised. Z-scores give a measure of how far a result is from the consensus value (i.e. the median), and gives a "score" to each result relative to the other results in the group.
A z-score with an absolute value less than or equal to 2.0 is considered to be satisfactory, whereas, a z-score with an absolute value greater than or equal to 3.0 is considered to be an outlier and is marked by the symbol “§”. Laboratories are also encouraged to review results which have an absolute z-score value between 2.0 and 3.0 (i.e. 2.0 < |z-score| < 3.0). These are considered to be questionable results.
Each determination was examined for outliers with all methods pooled. The table on
page 25 summarises the outlier results detected. 3.2 Results Tables and Summary Statistics The tables in Appendix A contain the results returned by each laboratory, including
the code number for the method used and the robust z-score calculated for each result.
Results have been entered exactly as reported by participants. That is, laboratories
which did not report results to the precision (i.e. number of significant figures) requested on the Results Sheet have not been rounded to the requested precision before being included in the statistical analysis.
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A list of summary statistics appears at the bottom of each of the results tables and consists of:
- No. of Results: the total number of results for that test/sample;
- Median: the middle value of the results;
- Normalised IQR: the normalised interquartile range of the results;
- Uncertainty of the Median: a robust estimate of the standard deviation of the Median;
- Robust CV: the robust coefficient of variation expressed as a percentage, i.e. 100 x Normalised IQR / Median;
- Minimum: the lowest laboratory result;
- Maximum: the highest laboratory result; and
- Range: the difference between the Maximum and Minimum.
The median is a measure of the centre of the data. The normalised IQR is a measure of the spread of the results. It is calculated by multiplying the interquartile range (IQR) by a correction factor, which converts the IQR to an estimate of the standard deviation. The IQR is the difference between the upper and lower quartiles (i.e. the values above and below which a quarter of the results lie, respectively). For normally distributed data, the uncertainty of the median is approximated by:
��2 ������
√�
� = number of results. Please see reference [1] for further details on these robust summary statistics.
3.3 Ordered Z-score Charts The charts in Appendix A indicate each laboratory's robust z-score, in order of
magnitude, marked with its laboratory code number. From these charts, each laboratory can readily compare its performance relative to the other laboratories.
These charts contain solid lines at +3.0 and -3.0, so that outliers are clearly
identifiable as those laboratories whose "bar" extends beyond these "cut-off" lines. The y-axis of these charts has been limited, so very large z-scores appear to extend beyond the chart boundary.
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4. PTA and Technical Adviser’s Comments 4.1 Metrological Traceability and Measurement Uncertainty of Assigned Values
Consensus values (median) derived from participants’ results are used in this program. These values are not metrologically traceable to an external reference. Sample preparation was undertaken according to Global Proficiency Ltd’s Standard Operating Procedures to ensure samples were fit-for-purpose, homogeneous and stable. Solutions were stable and homogeneous, and medians obtained from this proficiency round were in consistent agreement with the expected levels (dope concentration), as shown in Table 1. Samples PTA 1 and PTA 2 were prepared from Ammonium Chloride, Sulphanilamide and Potassium Dihydrogen Orthophosphate in distilled water. Sample PTA 3 was prepared from Nicotinic Acid and Tetra Potassium Pyrophosphate in distilled water. All samples were preserved with Sulphuric Acid. The sample format was designed so that two samples had unbound target analyte, with a more challenging third sample which had organically bound analyte, requiring rigorous digestion prior to being analysed. This was intended to provide more realistic and demanding samples for analysis while maintaining homogeneity and stability, continuity with previous rounds, and challenging the ability to troubleshoot any problems. As the assigned value for each analyte in this program is the median of the results submitted by the participants, the uncertainty of the median for each analyte has been calculated and is presented in Table 1 below together with the average analyte recovery data. Table 1. Comparison of expected levels (dope concentration) and proficiency medians. The values of the calculated uncertainty of the median are also presented.
Analyte Sample Dope
Concentration (mg/L)
Median (mg/L)
Analyte Recovery
(%)
Uncertainty of the median
(mg/L)
Total Kjeldahl Nitrogen
PTA 1 7.5 7.070 94.3% 0.117 [1.7%]
PTA 2 35 33.90 96.9% 0.48 [1.4%]
PTA 3 15 14.30 95.3% 0.31 [2.2%]
Total Phosphorus
PTA 1 5 4.990 99.8% 0.039 [0.8%]
PTA 2 1.3 1.240 95.4% 0.018 [1.5%]
PTA 3 7 7.510 107.3% 0.073 [1.0%]
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Average Total Kjeldahl Nitrogen (TKN) recoveries were comparable to those published in APHA 4500 – Norg B (Macro-Kjeldahl Method), which ranged between 87.7-101% recovery of Nicotinic Acid in the concentration range 5-20 mg/L. APHA 4500 – Norg D (Block Digestion and Flow Injection Analysis) predicted Nitrogen recoveries between 81%-134% for spiked natural samples. Total Phosphorus recoveries were also similar to those published in APHA (90.2-108.9%).
4.2 Analysis of Round 186 Results
4.2.1 Total Kjeldahl Nitrogen (TKN) Table 2 compares the TKN medians and robust CVs from this round to those obtained in previous PTA rounds, and in many cases laboratories performed better than previously observed. These CV were however, a little higher than those published in APHA 4500 – Norg B (Macro-Kjeldahl Method), where relative standard deviations (RSD) were between 0.84%-3.46% for concentration ranges of 5-20 mg/L. This published precision data was based on repeatability of various analysts, rather than true reproducibility between different laboratories, where a much larger RSD would be expected. APHA 4500 – Norg D (Block Digestion and Flow Injection Analysis) published RSD of between 3.3%-7.3%, which were closer to CVs observed in this round. Table 2. Comparison of current round variability and proficiency medians of TKN testing with the results of the previous two rounds.
Round Sample Median (mg/L) Robust CV (%) No. of Res ults
This study
PTA 1 7.070 6.2 22
PTA 2 33.90 5.6 24
PTA 3 14.30 8.3 23
Report 815
PTA 1 8.235 5.2 28
PTA 2 25.50 7.8 28
PTA 3 11.40 13.9 27
Report 725
Sample 1 10.60 12.4 35
Sample 2 12.90 5.7 35
Sample 3 12.30 11.8 35
Only a slight increase in CV was observed for the more challenging sample PTA 3 (8.3%) when compared to the more easily digestible samples PTA 1 and PTA 2 (6.2% and 5.6%, respectively). This is a marked improvement over previous rounds. Bias / Accuracy
TKN testing was successfully performed, with satisfactory results (|z-scores| ≤ 2.0) ranging between 6.20 – 7.94 mg/L for sample PTA 1, 30.12 – 37.68 mg/L for sample PTA 2 and 11.93 – 16.67 mg/L for sample PTA 3. Out of 22 participants for sample PTA 1, 24 participants for sample PTA 2 and 23 participants for sample PTA 3, two questionable results (2.0 < |z-scores| < 3.0) were
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obtained for each sample (PTA 1 - laboratories 143 and 185, PTA 2 - laboratories 143 and 633, PTA 3 - laboratories 269 and 556). Four outlier results (|z-scores| ≥ 3.0) were obtained for sample PTA 1 requiring follow-up action by laboratories 150, 269, 480 and 514. Three outlier results were obtained for sample PTA 2, requiring follow-up action by laboratories 150, 514 and 646b. Five outlier results were obtained for sample PTA 3, requiring follow-up action by laboratories 150, 185, 242, 508 and 587.
Laboratory 150 appears to have a systematic error in their TKN method as the reported results for all three samples were consistently below the median, indicating a negative bias.
The TKN dataset formed a normal distribution with no significant bias attributable to any digestion / analysis method (Figures 1 to 3). The most frequently used method to determine TKN was APHA 4500 – Norg B (Macro-Kjeldahl Method), which was used by approximately 36% of participants. Method APHA 4500 – Norg D (Block Digestion and Flow Injection Analysis) was the second most frequently applied digestion / analysis method, used by approximately 22% of participants. Calculation methods were used by approximately 29% of participants.
Figure 1. Spread of results for TKN testing of sample PTA 1, with a median concentration of 7.070 mg/L.
0
2
4
6
8
10
12
2.8 3.3 3.8 4.3 4.8 5.3 5.8 6.3 6.8 7.3 7.8 8.3 8.8 9.3
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen - Sample PTA 1
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
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Figure 2. Spread of results for TKN testing of sample PTA 2, with a median concentration of 33.90 mg/L.
Figure 3. Spread of results for TKN testing of sample PTA 3, with a median concentration of 14.30 mg/L.
0
2
4
6
8
10
12
15 17 19 21 23 25 27 29 31 33 35 37 39 41
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen - Sample PTA 2
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen - Sample PTA 3
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
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Catalyst
A large number of participants in this round (approximately 45%) used the Copper catalyst in the digestion of TKN, with a modest number of laboratories reporting Persulphate, Selenium or other catalysts. One participant indicated the use of digestion procedures instead of a catalyst while five participants did not state any catalyst or digestion. Figures 4 to 6 show the distribution of results based on the catalyst used, with no obvious trend in results.
Figure 4. Spread of results for TKN testing of sample PTA 1, based on catalyst.
0
2
4
6
8
10
12
2.8 3.3 3.8 4.3 4.8 5.3 5.8 6.3 6.8 7.3 7.8 8.3 8.8 9.3
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Catalyst - Sample PTA 1
Mercury
Copper
Selenium
Persulphate digestion
Other
None Stated
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Figure 5. Spread of results for TKN testing of sample PTA 2, based on catalyst.
Figure 6. Spread of results for TKN testing of sample PTA 3, based on catalyst.
0
2
4
6
8
10
12
15 17 19 21 23 25 27 29 31 33 35 37 39 41
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Catalyst - Sample PTA 2
Mercury
Copper
Selenium
Persulphate digestion
Other
None stated
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Catalyst - Sample PTA 3
Mercury
Copper
Selenium
Persulphate digestion
Other
None stated
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Final Ammonia Method
The most frequently used final Ammonia method in this round was the titrimetric method (APHA 4500 – NH3 C), which was used by approximately 29% of participants. The remaining laboratories used Flow Injection Analysis (APHA 4500 – NH3 H), modified standard methods, discrete analyser and salicylate continuous flow analysis (CFA). A relatively large number of laboratories (approximately 54%) did not report the final Ammonia method. This could be at least in part attributed to the sample analysis procedures being included with the digestion procedures in some methods. Figures 7 to 9 show the distribution of overall TKN results based on the Ammonia analysis method.
Figure 7. Spread of results for TKN testing of sample PTA 1, based on final Ammonia method.
0
2
4
6
8
10
12
2.8 3.3 3.8 4.3 4.8 5.3 5.8 6.3 6.8 7.3 7.8 8.3 8.8 9.3
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Final Ammonia Method - Sampl e PTA 1
APHA 4500 – NH₃ C.
APHA 4500 – NH₃ H.
Modified StandardMethod
Discrete Analyser
Salicilate CFA
None stated
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Figure 8. Spread of results for TKN testing of sample PTA 2, based on final Ammonia method.
Figure 9. Spread of results for TKN testing of sample PTA 3, based on final Ammonia method.
0
2
4
6
8
10
12
15 17 19 21 23 25 27 29 31 33 35 37 39 41
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Final Ammonia Method - Sampl e PTA 2
APHA 4500 – NH₃ C.
APHA 4500 – NH₃ H.
Modified StandardMethod
Discrete Analyser
Salicilate CFA
None stated
0
2
4
6
8
10
12
14
0 2 4 6 8 10 12 14 16 18 20 22 24 26
Fre
quen
cy
Results (mg/L)
Total Kjeldahl Nitrogen Final Ammonia Method - Sampl e PTA 3
APHA 4500 – NH₃ C.
APHA 4500 – NH₃ H.
Modified StandardMethod
Discrete Analyser
Salicilate CFA
None stated
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Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 10 to 12. On average, approximately 80% of participants submitted MU information. Most of the stated MUs accurately reflect the difference between the median and the participant’s result for these proficiency samples. Nine laboratories submitted MU results that did not encompass the assigned true value (median) at least for one of the samples tested. A t-test of all the results (outliers removed), indicated that the overall reproducibility for TKN testing in this round was 7.070 ± 0.932 mg/L (13.2%) for sample PTA 1, 33.90 ± 3.67 mg/L (10.8%) for sample PTA 2 and 14.30 ± 2.51 mg/L (17.6%) for sample PTA 3.
Figure 10. MU for TKN testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 0.932 mg/L in this round, shown as a dashed line.
0
1
2
3
4
5
0 0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Kjeldahl Nitrogen ± MU - Sample PTA 1
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
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Figure 11. MU for TKN testing of sample PTA 2, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 3.67 mg/L in this round, shown as a dashed line.
Figure 12. MU for TKN testing of sample PTA 3, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 2.51 mg/L in this round, shown as a dashed line.
0
1
2
3
4
5
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Kjeldahl Nitrogen ± MU - Sample PTA 2
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
0
1
2
3
4
5
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Kjeldahl Nitrogen ± MU - Sample PTA 3
APHA 4500 – Norg B.
APHA 4500 – Norg D.
ISO 5663–1984
Discrete Analyser
Calculation
Other
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Figures 13 to 15 below present the results of TKN testing and the reported MU, compared to the median. The uncertainty of the median was also presented as the dotted line either side of the median.
Figure 13. TKN - Results of sample PTA 1, including MU, compared to the median.
Figure 14. TKN - Results of sample PTA 2, including MU, compared to the median.
4.00
5.00
6.00
7.00
8.00
9.00
10.00
135
143
185
269
322
350
422
480
514
556
567
587
633
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Kjeldahl Nitrogen - Sample PTA 1
Result ± MU Median Uncertainty of the Median
20
25
30
35
40
45
135
143
185
269
322
350
422
480
514
556
567
587
622
633
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Kjeldahl Nitrogen - Sample PTA 2
Result ± MU Median Uncertainty of the Median
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Figure 15. TKN - Results of sample PTA 3, including MU, compared to the median. As shown in Figures 13 to 15, laboratories 185, 269, 322, 480, 514, 556, 587, 633 and 646b were further from the assigned value than was encompassed by their MU for at least one of their results, and are recommended to re-examine their quality control procedures (APHA 1020 and 4020 B), MU calculations, or both. Based on the most difficult to analyse samples (PTA 3), laboratory MU would be expected to be somewhere between 4.3% and 24.9% for TKN testing. Of lesser concern, laboratory 135 submitted a MU for sample PTA 3 that was smaller than the uncertainty of the assigned value. If they find that their results are further from the median than their MU encompasses, on successive proficiency rounds, they may wish to re-examine their measurement uncertainty. On the whole, laboratories have a very good understanding of their TKN measurement uncertainty, and are submitting realistic MU values.
5
10
15
20
25
135
143
185
269
322
350
422
480
514
556
567
587
622
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Kjeldahl Nitrogen - Sample PTA 3
Result ± MU Median Uncertainty of the Median
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4.2.2 Total Phosphorus Table 3 compares the Total Phosphorus medians and robust CVs from this round to those obtained in previous PTA rounds. Table 3. Comparison of current round variability and proficiency medians of Total Phosphorus testing with the results of the previous two rounds.
Round Sample Median (mg/L) Robust CV (%) No. of Res ults
This study
PTA 1 4.990 3.5 32
PTA 2 1.240 6.9 34
PTA 3 7.510 4.4 32
Report 815
PTA 1 4.250 5.4 33
PTA 2 1.110 6.3 34
PTA 3 2.305 9.5 34
Report 725
Sample 1 1.490 9.0 42
Sample 2 1.200 6.8 42
Sample 3 1.950 8.3 42
Bias / Accuracy Total Phosphorus testing was successfully performed, with satisfactory results (|z-scores| ≤ 2.0) ranging between 4.64 – 5.34 mg/L for sample PTA 1, 1.07 – 1.41 mg/L for sample PTA 2 and 6.85 – 8.17 for sample PTA 3. Out of 32 participants for sample PTA 1, four questionable results (2.0 < |z-scores| < 3.0) were obtained (laboratories 143, 408, 508 and 646b). Out of 34 participants for sample PTA 2, three questionable results were obtained (laboratories 143, 263 and 325). Out of 32 participants for sample PTA 3, four questionable results were obtained (laboratories 143, 160, 408 and 508). Six outlier results (|z-scores| ≥ 3.0) were obtained for sample PTA 1 requiring follow-up action by laboratories 150, 215, 263, 269, 322 and 376. Four outlier results were obtained for sample PTA 2, requiring follow-up action by laboratories 150, 213, 376 and 646b. Three outlier results were obtained for sample PTA 3, requiring follow-up action by laboratories 150, 215 and 269. Laboratory 150 may have made a dilution error when preparing their samples as their results are consistently below the median. The Total Phosphorus dataset formed a normal distribution with no significant bias attributable to any one analysis method (Figures 16 to 18). There was a large variety of methods used for Total Phosphorus analysis in this round, including: Vanado-molybdophosphoric Acid Colorimetric, Stannous Chloride, Ascorbic Acid, FIA, Persulfate, Ammonium Molybdate, Discrete Analyser, HACH test kits, etc.
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Figure 16. Spread of results for Total Phosphorus testing of sample PTA 1, with a median concentration of 4.990 mg/L.
Figure 17. Spread of results for Total Phosphorus testing of sample PTA 2, with a median concentration of 1.240 mg/L.
0
4
8
12
16
20
24
1.75 2.25 2.75 3.25 3.75 4.25 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25
Fre
quen
cy
Results (mg/L)
Total Phosphorus - Sample PTA 1
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
Not specified
0
4
8
12
16
20
24
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7
Fre
quen
cy
Results (mg/L)
Total Phosphorus - Sample PTA 2
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
Not specified
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Figure 18. Spread of results for Total Phosphorus testing of sample PTA 3, with a median concentration of 7.510 mg/L.
0
2
4
6
8
10
12
14
16
18
2.75 3.25 3.75 4.25 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25
Fre
quen
cy
Results (mg/L)
Total Phosphorus - Sample PTA 3
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
Not specified
19
SD 9.17.10
Digestion Method
The most frequently used digestion method to determine Total Phosphorus was the APHA 4500 – P B5 (Persulfate Method), which was used by approximately 41% of participants. Figures 19 to 21 show the distribution of results based on the digestion method used, with no obvious trend in results.
Figure 19. Spread of results for Total Phosphorus testing of sample PTA 1, based on digestion method.
0
4
8
12
16
20
24
1.75 2.25 2.75 3.25 3.75 4.25 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25
Fre
quen
cy
Results (mg/L)
Total Phosphorus Digestion Method - Sample PTA 1
APHA 4500 – P B3.
APHA 4500 – P B4.
APHA 4500 – P B5.
US EPA 200.2
In-house method
Other
Copper
None stated
20
SD 9.17.10
Figure 20. Spread of results for Total Phosphorus testing of sample PTA 2, based on digestion method.
Figure 21. Spread of results for Total Phosphorus testing of sample PTA 3, based on digestion method.
0
4
8
12
16
20
24
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7
Fre
quen
cy
Results (mg/L)
Total Phosphorus Digestion Method - Sample PTA 2
APHA 4500 – P B3.
APHA 4500 – P B4.
APHA 4500 – P B5.
US EPA 200.2
In-house method
Other
Copper
None stated
0
2
4
6
8
10
12
14
16
18
2.75 3.25 3.75 4.25 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 9.25
Fre
quen
cy
Results (mg/L)
Total Phosphorus Digestion Method - Sample PTA 3
APHA 4500 – P B3.
APHA 4500 – P B4.
APHA 4500 – P B5.
US EPA 200.2
In-house method
Other
Copper
None stated
21
SD 9.17.10
Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 22 to 24. On average, approximately 80% of participants submitted MU information. Most of the stated MUs accurately reflect the difference between the median and the participant’s result for these proficiency samples. Nine laboratories submitted MU results that did not encompass the assigned true value (median) for at least one of the samples tested. A t-test of all the results (outliers removed), indicated that the overall reproducibility for Total Phosphorus testing in this round was 4.990 ± 0.450 mg/L (9.0%) for sample PTA 1, sample PTA 2 was 1.240 ± 0.200 mg/L (16.1%) and 7.510 ± 0.825 mg/L (11.0%) for sample PTA 3.
Figure 22. MU for Total Phosphorus testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 0.450 mg/L in this round, shown as a dashed line.
0
1
2
3
4
5
6
7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Phosphorus ± MU - Sample PTA 1
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
22
SD 9.17.10
Figure 23. MU for Total Phosphorus testing of sample PTA 2, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 0.200 mg/L in this round, shown as a dashed line.
Figure 24. MU for Total Phosphorus testing of sample PTA 3, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 0.825 mg/L in this round, shown as a dashed line.
0
1
2
3
4
5
6
7
8
9
0 0.03 0.06 0.09 0.12 0.15 0.18 0.21 0.24 0.27 0.3 0.33 0.36 0.39
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Phosphorus ± MU - Sample PTA 2
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
0
1
2
3
4
5
6
7
0 0.15 0.3 0.45 0.6 0.75 0.9 1.05 1.2 1.35 1.5 1.65 1.8 1.95
Fre
quen
cy
Measurement Uncertainty (mg/L)
Total Phosphorus ± MU - Sample PTA 3
APHA 4500 – P C.
APHA 4500 – P D.
APHA 4500 – P E.
APHA 4500 – P F.
APHA 4500 – P G.
APHA 4500 – P H.
APHA 4500 – P J.
EN ISO 6878–2004
Modified Standard Method
Discrete Analyser
Test Kit, Colorimeter
Other
23
SD 9.17.10
Figures 25 to 27 below present the results of Total Phosphorus testing and the reported MU, compared to the median. The uncertainty of the median was also presented as the dotted line either side of the median.
Figure 25. Total Phosphorus - Results of sample PTA 1, including MU, compared to the median. The outlier result of laboratory 269 is not shown.
Figure 26. Total Phosphorus - Results of sample PTA 2, including MU, compared to the median.
3.5
4
4.5
5
5.5
6
6.5
135
143
185
209
213
322
350
408
422
449
456
480
508
514
556
567
587
598
622
633
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Phosphorus - Sample PTA 1
Result ± MU Median Uncertainty of the Median
0.8
1
1.2
1.4
1.6
1.8
135
143
185
209
213
242
269
322
350
408
422
449
456
480
508
514
556
567
587
598
622
633
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Phosphorus - Sample PTA 2
Result ± MU Median Uncertainty of the Median
24
SD 9.17.10
Figure 27. Total Phosphorus - Results of sample PTA 3, including MU, compared to the median. The outlier result of laboratory 269 is not shown. As shown in Figures 25 to 27, laboratories 143, 213, 242, 322, 449, 508, 646b and 676 were further from the assigned value than was encompassed by their measurement uncertainty for at least one of their results and are recommended to re-examine their MU calculations. Based on the sample with the largest CV (PTA 2), laboratory MU would be expected to be somewhere between 3.0% and 20.6% for Total Phosphorus testing. On the whole, the remainder of laboratories have a very good understanding of their Total Phosphorus measurement uncertainty and are submitting realistic MU values.
4.3 Analysis of Results by Method Groups
In order for methods to be grouped for analysis, PTA requires at least 11 sets of results from the same method group. As there were less than 11 results submitted for each method, reliable conclusions cannot be drawn from analysing grouped methods on this occasion. Therefore, results from all method groups have been pooled for analysis.
5.5
6
6.5
7
7.5
8
8.5
9
9.5
135
143
185
209
213
322
350
408
422
449
456
480
508
514
556
567
587
598
633
646a
646b 648
660
676
Res
ults
(mg/
L)
Laboratory Code
Total Phosphorus - Sample PTA 3
Result ± MU Median Uncertainty of the Median
25
SD 9.17.10
5. Outlier Results Laboratories reporting results that have been identified as outliers are listed in Table 4 below.
Table 4. Laboratory results identified as outliers for each analysis performed.
Lab Code
Analysis
Total Kjeldahl Nitrogen Total Phosphorus
PTA 1 PTA 2 PTA 3 PTA 1 PTA 2 PTA 3
150 § § § § § §
185 §
213 §
215 § §
242 §
263 §
269 § § §
322 §
376 § §
480 §
508 §
514 § §
587 §
646b § §
Note: 1. A “§” indicates the occurrence of a z-score outlier result (i.e. those results for which
|z-score| ≥ 3.0).
6. References
[1] Guide to Proficiency Testing Australia, 2014 (This document can be found on the PTA website, www.pta.asn.au)
[2] APHA Standard Methods For the Examination of Water and Wastewater, 2012. 22nd Edition by APHA, AWWA, WEF. American Public Health Association, Washington DC, USA.
SD 9.17.10
APPENDIX A
Results and Data Analysis Total Kjeldahl Nitrogen .......................................................................................................... A1
Total Phosphorus .................................................................................................................. A7
SD 9.17.10
Total Kjeldahl Nitrogen Results
Samples PTA 1, PTA 2 and PTA 3
A1
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)
Results by Laboratory Code
Sample PTA 1
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Catalyst Code3
Final Ammonia Method Code3
135 6.90 ± 0.7 -0.39 26 40 # 143 8.1 ± 1.3 2.35 38 40 56 150 3.08 # -9.08 § 26 40 # 160 7.22 # 0.34 24 40 45 185 8.02 ± 0.9 2.16 24 40 45 263 7.30 # 0.52 24 41 45 269 5.558 ± 0.555 -3.44 § 30 41 # 322 7.18 ± 0.1 0.25 37 # # 350 7.38 ± 1.62 0.71 37 # # 422 6.83 ± 0.68 -0.55 37 44 # 480 8.43 ± 1.01 3.10 § 26 39 # 508 6.96 # -0.25 26 39 53 514 5.38 ± 0.382 -3.85 § 34 40 # 556 7.05 ± 0.3 -0.05 24 40 45 567 7.52 ± 0.52 1.02 24 40 52 587 7.48 ± 0.82 0.93 37 44 # 633 7.46 ± 0.37 0.89 24 44 45 646a 7.07 ± 1.2 0.00 24 40 45 646b 6.58 ± 0.66 -1.12 37 # # 648 7.03 ± 1.76 -0.09 26 # 50 660 6.31 ± 0.97 -1.73 24 40 45 676 7.07 ± 1.0 0.00 37 # # No of Results: 22
Median: 7.070
Normalised IQR: 0.439
Uncertainty of the Median:
0.117
Robust CV: 6.2%
Minimum: 3.08
Maximum: 8.43
Range: 5.35
1 Where reported, results are shown with their corresponding measurement uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-scores are
calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method, catalyst and final Ammonia method code descriptions.
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)- Sample PTA 1 - Robus t Z-Scores
Ordered R
obust Z-S
core Chart
Total K
jeldahl Nitrogen (T
KN
)- Sam
ple PT
A 1
A2
150
514 26
9
660 64
6b 422
135
508
648
556
646a
676
322
160
263
350
633
587
567
185
143 48
0
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
A3
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)
Results by Laboratory Code
Sample PTA 2
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Catalyst Code3
Final Ammonia Method Code3
135 32.4 ± 3.5 -0.79 26 40 # 143 38 ± 6.5 2.17 38 40 56 150 15.6 # -9.68 § 26 40 # 160 33.1 # -0.42 24 40 45 185 34.4 ± 3.7 0.26 24 40 45 242 34.0 # 0.05 24 40 # 263 35.0 # 0.58 24 41 45 269 33.65 ± 3.365 -0.13 30 41 # 322 35.5 ± 0.1 0.85 37 # # 350 34.5 ± 7.60 0.32 37 # # 422 33.8 ± 3.4 -0.05 37 44 # 480 35.7 ± 4.3 0.95 26 39 # 508 33.3 # -0.32 26 39 53 514 27.6 ± 1.960 -3.33 § 34 40 # 556 34.2 ± 1.4 0.16 24 40 45 567 35.1 ± 2.5 0.63 24 40 52 587 36.5 ± 4.01 1.38 37 44 # 622 31.0 ± 5.2 -1.53 37 # # 633 37.9 ± 1.9 2.12 24 44 45 646a 32.5 ± 5.5 -0.74 24 40 45 646b 24.7 ± 2.5 -4.87 § 37 # # 648 34.8 ± 8.70 0.48 26 # 50 660 32.2 ± 4.96 -0.90 24 40 45 676 33.7 ± 2.0 -0.11 37 # # No of Results: 24
Median: 33.90
Normalised IQR: 1.89
Uncertainty of the Median:
0.48
Robust CV: 5.6%
Minimum: 15.6
Maximum: 38
Range: 22.4
1 Where reported, results are shown with their corresponding measurement uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-scores are
calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method, catalyst and final Ammonia method code descriptions.
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)- Sample PTA 2 - Robus t Z-Scores
Ordered R
obust Z-S
core Chart
Total K
jeldahl Nitrogen (T
KN
)- Sam
ple PT
A 2
A4
150
646b
514
622 66
0
135
646a 16
0
508
269
676
422
242
556
185
350
648
263
567
322
480 58
7 633
143
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
A5
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)
Results by Laboratory Code
Sample PTA 3
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Catalyst Code3
Final Ammonia Method Code3
135 14.2 ± 0.2 -0.08 26 40 # 143 16 ± 2.7 1.43 38 40 56 150 0.5 # -11.63 § 26 40 # 160 14.1 # -0.17 24 40 45 185 6.09 ± 0.9 -6.92 § 24 40 45 242 19.4 # 4.30 § 24 40 # 263 12.8 # -1.26 24 41 45 269 11.567 ± 1.156 -2.30 30 41 # 322 15.6 ± 0.1 1.10 37 # # 350 15.2 ± 3.35 0.76 37 # # 422 14.9 ± 1.5 0.51 37 44 # 480 15.1 ± 1.8 0.67 26 39 # 508 5.88 # -7.10 § 26 39 53 514 13.5 ± 0.959 -0.67 34 40 # 556 16.8 ± 0.7 2.11 24 40 45 567 14.6 ± 1.1 0.25 24 40 52 587 19.5 ± 2.14 4.38 § 37 44 # 622 14.3 ± 2.8 0.00 37 # # 646a 14.1 ± 2.4 -0.17 24 40 45 646b 14.2 ± 1.4 -0.08 37 # # 648 14.8 ± 3.70 0.42 26 # 50 660 13.7 ± 2.1 -0.51 24 40 45 676 15.2 ± 1.0 0.76 37 # # No of Results: 23
Median: 14.30
Normalised IQR: 1.19
Uncertainty of the Median:
0.31
Robust CV: 8.3%
Minimum: 0.5
Maximum: 19.5
Range: 19.0
1 Where reported, results are shown with their corresponding measurement uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-scores are
calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method, catalyst and final Ammonia method code descriptions.
SD 9.17.10
Total Kjeldahl Nitrogen (TKN)- Sample PTA 3 - Robus t Z-Scores
Ordered R
obust Z-S
core Chart
Total K
jeldahl Nitrogen (T
KN
)- Sam
ple PT
A 3
A6
150
508
185
269
263 51
4
660 16
0
646a 13
5
646b
622
567
648
422
480
350
676 32
2 143 55
6
242
587
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
SD 9.17.10
Total Phosphorus
Samples PTA 1, PTA 2 and PTA 3
A7
SD 9.17.10
Total Phosphorus
Results by Laboratory Code Sample PTA 1
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
135 4.98 ± 0.5 -0.06 5 17
143 4.6 ± 0.27 -2.22 4 19
150 2.13 # -16.24 § 6 40
160 4.94 # -0.28 # #
185 5.13 ± 0.49 0.80 1 19
209 5.01 ± 0.50 0.11 3 19
213 5.11 ± 0.2 0.68 15 19
215 5.54 # 3.12 § 16 #
263 4.20 # -4.49 § 4 18
269 7.873 ± 0.787 16.38 § 11 23
322 5.55 ± 0.01 3.18 § 12 21
350 5.16 ± 0.96 0.97 8 19
376 5.74 # 4.26 § 1 18
408 5.49 ± 0.52 2.84 2 #
422 5.11 ± 0.51 0.68 8 19
449 4.93 ± 0.02 -0.34 16 #
456 4.92 ± 0.18 -0.40 12 21
480 4.91 ± 0.60 -0.45 4 20
508 4.57 ± 0.50 -2.39 6 19
514 4.71 ± 0.391 -1.59 13 19
548 5.0 # 0.06 15 23
556 5.10 ± 0.48 0.62 3 18 1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
A8
SD 9.17.10
Total Phosphorus - cont. Results by Laboratory Code
Sample PTA 1
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
567 5.13 ± 0.18 0.80 4 21
587 5.14 ± 1.05 0.85 16 21
598 5.28 ± 0.54 1.65 16 21
622 5.10 ± 0.67 0.62 6 19
633 4.92 ± 0.25 -0.40 16 21
646a 4.85 ± 0.23 -0.80 3 19
646b 4.49 ± 0.45 -2.84 13 19
648 4.96 ± 0.992 -0.17 16 21
660 4.85 ± 0.36 -0.80 2 19
676 4.98 ± 0.10 -0.06 6 19 No of Results: 32
Median: 4.990
Normalised IQR: 0.176
Uncertainty of the Median:
0.039
Robust CV: 3.5%
Minimum: 2.13
Maximum: 7.873
Range: 5.743
1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
SD 9.17.10
Total Phosphorus- Sample PTA 1 - Robust Z-Scores
Ordered R
obust Z-S
core Charts
Total P
hosphorus- Sam
ple PT
A 1
A9
Robust Z-Scores
150 26
3
646b 50
8
143 51
4 646a 66
0 480
456
633
449
160
648
135
676
-5
-4
-3
-2
-1
0
1
2
3
4
5z-
scor
e
lab code
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
A10
SD 9.17.10
Total Phosphorus
Results by Laboratory Code Sample PTA 2
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
135 1.25 ± 0.2 0.12 5 17
143 1.0 ± 0.05 -2.82 4 19
150 0.46 # -9.15 § 6 40
160 1.18 # -0.70 # #
185 1.26 ± 0.20 0.23 1 19
209 1.22 ± 0.12 -0.23 3 19
213 1.56 ± 0.1 3.75 § 15 19
215 1.37 # 1.52 16 #
242 1.15 ± 0.05 -1.06 16 19
263 1.04 # -2.35 4 18
269 1.374 ± 0.137 1.57 11 23
322 1.28 ± 0.01 0.47 12 21
325 1.006 # -2.74 16 #
350 1.28 ± 0.24 0.47 8 19
376 2.56 # 15.48 § 1 18
408 1.19 ± 0.11 -0.59 2 #
422 1.31 ± 0.13 0.82 8 19
449 1.22 ± 0.03 -0.23 16 #
456 1.22 ± 0.05 -0.23 12 21
480 1.38 ± 0.17 1.64 4 20
508 1.11 ± 0.12 -1.52 6 19
514 1.24 ± 0.103 0.00 13 19 1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
A11
SD 9.17.10
Total Phosphorus - cont. Results by Laboratory Code
Sample PTA 2
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
548 1.24 # 0.00 15 23
556 1.31 ± 0.12 0.82 3 18
567 1.23 ± 0.04 -0.12 4 21
587 1.36 ± 0.28 1.41 16 21
598 1.27 ± 0.14 0.35 16 21
622 1.30 ± 0.23 0.70 6 19
633 1.29 ± 0.06 0.59 16 21
646a 1.20 ± 0.06 -0.47 3 19
646b 0.96 ± 0.10 -3.28 § 13 19
648 1.18 ± 0.236 -0.70 16 21
660 1.27 ± 0.12 0.35 2 19
676 1.23 ± 0.05 -0.12 6 19 No of Results: 34
Median: 1.240
Normalised IQR: 0.085
Uncertainty of the Median:
0.018
Robust CV: 6.9%
Minimum: 0.46
Maximum: 2.56
Range: 2.10
1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
SD 9.17.10
Total Phosphorus- Sample PTA 2 - Robust Z-Scores
Ordered R
obust Z-S
core Charts
Total P
hosphorus- Sam
ple PT
A 2
A12
Robust Z-Scores
150
646b 14
3
325 26
3 508 24
2 160
648
408
646a 20
9
449
456
567
676
514
-5
-4
-3
-2
-1
0
1
2
3
4
5z-
scor
e
lab code
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
A13
SD 9.17.10
Total Phosphorus
Results by Laboratory Code Sample PTA 3
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
135 7.51 ± 0.8 0.00 5 17
143 6.6 ± 0.39 -2.74 4 19
150 3.12 # -13.23 § 6 40
160 6.57 # -2.83 # #
185 7.68 ± 1.04 0.51 1 19
209 7.49 ± 0.75 -0.06 3 19
213 7.84 ± 0.3 0.99 15 19
215 8.51 # 3.01 § 16 #
242 7.4 # -0.33 16 19
263 7.50 # -0.03 4 18
269 3.698 ± 0.369 -11.49 § 11 23
322 8.07 ± 0.01 1.69 12 21
350 7.61 ± 1.41 0.30 8 19
376 7.87 # 1.09 1 18
408 8.24 ± 0.79 2.20 2 #
422 7.88 ± 0.79 1.12 8 19
449 7.48 ± 0.11 -0.09 16 #
456 7.60 ± 0.29 0.27 12 21
480 7.20 ± 0.8 -0.93 4 20
508 6.66 ± 0.73 -2.56 6 19
514 7.32 ± 0.608 -0.57 13 19
548 7.30 # -0.63 15 23 1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
A14
SD 9.17.10
Total Phosphorus - cont. Results by Laboratory Code
Sample PTA 3
Lab Code Result ± MU1
(mg/L) Robust z-score2
Method Code3
Digestion Code3
556 7.62 ± 0.72 0.33 3 18
567 7.74 ± 0.27 0.69 4 21
587 7.80 ± 1.59 0.87 16 21
598 7.95 ± 0.80 1.33 16 21
633 7.51 ± 0.38 0.00 16 21
646a 7.37 ± 0.35 -0.42 3 19
646b 7.05 ± 0.71 -1.39 13 19
648 7.58 ± 1.52 0.21 16 21
660 7.41 ± 0.61 -0.30 2 19
676 7.75 ± 0.10 0.72 6 19 No of Results: 32
Median: 7.510
Normalised IQR: 0.332
Uncertainty of the Median:
0.073
Robust CV: 4.4%
Minimum: 3.12
Maximum: 8.51
Range: 5.39
1 Where reported, results are shown with their corresponding measurement
uncertainty (MU). 2 "§" denotes an outlier (i.e. those results for which |z-score| ≥ 3.0). Robust z-
scores are calculated as: z = (A - median) ÷ normalised IQR, where A is the participant laboratory's result.
3 Please refer to Appendix C (pages C3-C5) for method and digestion code descriptions.
SD 9.17.10
Total Phosphorus- Sample PTA 3 - Robust Z-Scores
Ordered R
obust Z-S
core Charts
Total P
hosphorus- Sam
ple PT
A 3
A15
Robust Z-Scores
150
269
160
143
508 64
6b 480 54
8
514
646a 24
2
660
449
209
263
135
-5
-4
-3
-2
-1
0
1
2
3
4
5z-
scor
e
lab code
-5
-4
-3
-2
-1
0
1
2
3
4
5
z-sc
ore
lab code
SD 9.17.10
APPENDIX B
Sample Homogeneity and Stability
Homogeneity and Stability Testing ........................................................................................ B1
B1
SD 9.17.10
Homogeneity and Stability Testing Samples for this program were obtained from Global Proficiency Ltd, New Zealand. As such, all samples are subjected to rigorous quality control and homogeneity / stability testing. A random selection of ten samples was chosen from sample sets PTA 1 and PTA 3 for homogeneity and stability testing. Seven of each set were stored frozen, the remaining three were subjected to 35ºC for three days for an accelerated ageing stability trial. The samples were then analysed in duplicate by Hill Laboratories, New Zealand. For sample set PTA 2, two samples were randomly selected, stored frozen in the same conditions as the homogeneity samples and subjected to a verification testing (one replicate per sample) by Hill Laboratories, New Zealand. Homogeneity and stability characteristics were assumed to be similar to samples PTA 1 and PTA 3, based on identical manufacturing procedure and sample handling. All stability samples showed no notable differences when compared to homogeneity samples. Based on the assumption that the rate of ageing doubles with every 7ºC elevated temperature, these samples were assumed stable for more than 96 days (3 days*2(35/7)) from the date of manufacture, for all analytes. From statistical analyses based on the results of this testing and rigorous quality control, it was considered that all samples were sufficiently homogeneous and stable, so that any results later identified as outliers should not be attributed to any notable sample variability. The results of homogeneity and stability testing are presented in Tables B1 to B3 below. Please note that the mean results for these tests are not intended to be used as reference values. Table B1. Homogeneity and stability testing of PTA 1 samples.
Round PTA 186
Samples PTA 1
Sample ID Total Kjeldahl Nitrogen (g/m3) Dissolved Reactive
Phosphorus (g/m3) Duplicate 1 Duplicate 2 Duplicate 1 Duplicate 2
Homogeneity H1 745.7 746.2 500.6 499.2 H2 747.7 745.7 506.2 503.4 H3 763.7 730.9 504.6 506.0 H4 761.7 770.9 502.4 504.2 H5 778.7 759.7 500.0 505.8 H6 781.7 763.7 501.6 506.4 H7 738.2 751.7 505.8 500.0
Stability S1 780.7 759.7 500.2 504.4 S2 745.7 756.7 493.8 503.4 S3 769.2 744.2 502.6 503.4
RSD 2.13% 1.54% 0.71% 0.48%
B2
SD 9.17.10
Table B2. Homogeneity testing of PTA 2 samples.
Round PTA 186
Samples PTA 2
Sample ID Total Kjeldahl Nitrogen (g/m3) Dissolved Reactive
Phosphorus (g/m3) Duplicate 1 Duplicate 2 Duplicate 1 Duplicate 2
Homogeneity H1 3462.7 128.199 H2 3447.7 128.599
RSD 0.31% 0.22% Table B3. Homogeneity and stability testing of PTA 3 samples.
Round PTA 186
Samples PTA 3
Sample ID Total Kjeldahl Nitrogen (g/m3) Dissolved Reactive
Phosphorus (g/m3) Duplicate 1 Duplicate 2 Duplicate 1 Duplicate 2
Homogeneity H1 1583.2 1490.9 772.5 767.2 H2 1558.2 1575.4 768.6 762.3 H3 1560.2 1602.9 764.4 746.6 H4 1535.2 1594.4 755.3 753.2 H5 1521.2 1486.4 752.9 753.9 H6 1573.7 1487.9 759.9 750.1 H7 1608.7 1582.9 755.0 745.9
Stability S1 1631.7 1680.4 749.0 750.4 S2 1551.2 1599.9 758.1 760.9 S3 1567.2 1626.9 761.3 769.3
RSD 2.09% 4.14% 0.95% 1.11%
SD 9.17.10
APPENDIX C
Documentation
Instructions to Participants .................................................................................................... C1
Method Codes ....................................................................................................................... C3
Results Sheet ........................................................................................................................ C6
SD 9.17.10
CHEMICAL ANALYSIS ROUND 186 Total Kjeldahl
Please note the following before commencing the analysis of the samples. 1. Samples
i)
ii)
iii)
Please Note:laboratory sample.
2. Sample Preparation
Caution:
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
Please report results for the diluted sample.
SD 9.17.10
CHEMICAL ANALYSIS ROUND 186
Total Kjeldahl Nitrogen, Total Phosphorus
**Please record (on the Results Sheet) the approximate tempe rature
Please note the following before commencing the analysis of the samples.
Samples
Three plastic The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabiliseH2SO4, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples must be thoroughly mixed prior to analysis.
The samples will require dilution in reagent grade waterPreparation
Please Note: laboratory sample.
Sample Preparation
Caution: Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any redissolved prior to dilution step.
Add approximately 900 mL reagent grade water to a one
Record bottle ID number. Open bottle.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
Bring to volume with reagent grade water.
Close with stopper and mix by inversion.
Test according to your normal procedures.
viii) Repeat steps
Please report results for the diluted sample.
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Nitrogen, Total Phosphorus
INSTRUCTIONS TO PARTICIPANTS
**Please record (on the Results Sheet) the approximate tempe rature
Please note the following before commencing the analysis of the samples.
Three plastic bottles labelled PTA 1, PTA 2 and PTA 3The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples must be thoroughly mixed prior to analysis.
The samples will require dilution in reagent grade waterPreparation steps below)
Where possible, proficiency testing samples should be treated as a routine laboratory sample.
Sample Preparation
Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any redissolved prior to dilution step.
Add approximately 900 mL reagent grade water to a one
Record bottle ID number. Open bottle.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
to volume with reagent grade water.
Close with stopper and mix by inversion.
Test according to your normal procedures.
Repeat steps i) to vii) for the second and third sample.
Please report results for the diluted sample.
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Nitrogen, Total Phosphorus
INSTRUCTIONS TO PARTICIPANTS
**Please record (on the Results Sheet) the approximate tempe rature of the samples upon receipt**
Please note the following before commencing the analysis of the samples.
bottles labelled PTA 1, PTA 2 and PTA 3The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples must be thoroughly mixed prior to analysis.
The samples will require dilution in reagent grade waterbelow).
ere possible, proficiency testing samples should be treated as a routine
Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any redissolved prior to dilution step.
Add approximately 900 mL reagent grade water to a one
Record bottle ID number. Open bottle.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
to volume with reagent grade water.
Close with stopper and mix by inversion.
Test according to your normal procedures.
for the second and third sample.
Please report results for the diluted sample.
C1
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
Nitrogen, Total Phosphorus
INSTRUCTIONS TO PARTICIPANTS
**Please record (on the Results Sheet) the approximate tempe rature of the samples upon receipt**
Please note the following before commencing the analysis of the samples.
bottles labelled PTA 1, PTA 2 and PTA 3The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples must be thoroughly mixed prior to analysis.
The samples will require dilution in reagent grade water
ere possible, proficiency testing samples should be treated as a routine
Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any
Add approximately 900 mL reagent grade water to a one
Record bottle ID number. Open bottle.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
to volume with reagent grade water.
Close with stopper and mix by inversion.
Test according to your normal procedures.
for the second and third sample.
Please report results for the diluted sample.
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
INSTRUCTIONS TO PARTICIPANTS
**Please record (on the Results Sheet) the approximate tempe rature of the samples upon receipt**
Please note the following before commencing the analysis of the samples.
bottles labelled PTA 1, PTA 2 and PTA 3, supplied by Global Proficiency Ltd. The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples must be thoroughly mixed prior to analysis.
The samples will require dilution in reagent grade water
ere possible, proficiency testing samples should be treated as a routine
Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any
Add approximately 900 mL reagent grade water to a one-litre volumetric flask.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
for the second and third sample.
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
INSTRUCTIONS TO PARTICIPANTS
**Please record (on the Results Sheet) the approximate tempe rature
Please note the following before commencing the analysis of the samples.
, supplied by Global Proficiency Ltd. The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
The samples will require dilution in reagent grade water (please follow the
ere possible, proficiency testing samples should be treated as a routine
Analysis must begin immediately after bottle is opened.
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any
litre volumetric flask.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
SEPTEMBER, 2015
**Please record (on the Results Sheet) the approximate tempe rature
, supplied by Global Proficiency Ltd. The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilise
, samples PTA 1 and PTA 2 to pH ~2, and sample PTA 3 to pH ~3.
(please follow the
ere possible, proficiency testing samples should be treated as a routine
Adjust bottle temperature to 20ºC and mix thoroughly to ensure any precipitate has fully
litre volumetric flask.
Using a volumetric pipette transfer 10.00 mL from the bottle into the flask.
SEPTEMBER, 2015
, supplied by Global Proficiency Ltd. The bottles contain approximately 22 mL of artificial potable water concentrate for analysis of Total Kjeldahl Nitrogen and Total Phosphorus. The concentrate samples are stabilised with
(please follow the Sample
ere possible, proficiency testing samples should be treated as a routine
precipitate has fully
C2
SD 9.17.10
3. Tests Requested
For each of the samples prepared from the three bottles:
i) Total Kjeldahl Nitrogen (TKN)
ii) Total Phosphorus (TP)
(It is recommended that a reagent water blank is analysed by the same method used to analyse the samples.)
If unable to perform the above please note this on your Results Sheet.
4. Safety
i) Samples are for laboratory use only.
ii) Participants should have sufficient experience and training to take the necessary precautions when handling the samples and reagent chemicals and during disposal.
iii) Use of personal protective equipment such as safety glasses, gloves, laboratory coats and fume hoods, where appropriate during the determinations, is recommended
5. Reporting
i) Report results using three significant figures (e.g.: 0.0123, 0.123, 1.23, 12.3).
ii) Report results in milligrams per litre (mg/L).
iii) Do not correct results for recovery.
iv) Select the appropriate method code for each test from the Method Code Table and record it on the Results Sheet.
v) Calculate the measurement uncertainty (MU) for each reported result. All estimates of MU must be given as a 95% confidence interval (coverage factor k ≈ 2) and reported in mg/L. Report MU using the same number of decimal places as for the result.
6. Testing should commence as soon as possible after receiving the samples and results reported
NO LATER THAN 2 OCTOBER 2015 to:
Delfina Mihaila Proficiency Testing Australia PO Box 7507 SILVERWATER NSW 2128 AUSTRALIA Phone: +612 9736 8397 Fax: +612 9743 6664 Email: [email protected]
7. For this program your laboratory has been allocated the code number shown on the attached
Results Sheet. All reference to your laboratory in reports associated with the program will be through this code number, thus ensuring the confidentiality of your results.
8. As a guide, ranges for the samples can be expected to be:
Analyte Range (mg/L) Total Kjeldahl Nitrigen (TKN) 5 - 50 Total Phosphorus (TP) 0.5 - 10
C3
SD 9.17.10
Method Codes to be used for the Results Sheet
ANALYSIS METHOD REFERENCE METHOD DESCRIPTION CODE
Total Phosphorus (TP)
APHA APHA 4500 – P C. Vanadomolybdophosphoric Acid Colorimetric Method 1
APHA 4500 – P D. Stannous Chloride Method 2
APHA 4500 – P E. Ascorbic Acid Method 3
APHA 4500 – P F. Automated Ascorbic Acid Reduction Method 4
APHA 4500 – P G. Flow Injection Analysis for Orthophosphate 5
APHA 4500 – P H. Manual Digestion and Flow Injection Analysis for Total Phosphorus 6
APHA 4500 – P I. In-line UV/Persulfate Digestion and Flow Injection Analysis for Total Phosphorus
7
APHA 4500 – P J. Persulfate Method for Simultaneous Determination of Total Nitrogen and Total Phosphorus
8
USEPA US EPA 0365.1 – 0.365.4 0365.1 Orthophosphate (as P) - Automated Colorimetry 0365.1 Phosphorus, All Forms - Colorimetric/Automated 0365.2 Phosphorus - manual colorimetric/1 reagent 0365.3 Phosphorus - colorimetric/ 2 reagents 0365.4 Phosphorus, Total -Colorimetric/Automated
9
ESS Method 230.1: Total Phosphorus and Total Kjeldahl Nitrogen, Semi-Automated Method
10
ISO / CEN EN ISO 6878:2004 Water Quality - Determination Of Phosphorus - Ammonium Molybdate Spectrometric Method
11
Other Modified Standard Method 12
Discrete Analyser 13
AA / FIA 14
Test Kit, Colorimeter (HACH, Fluka… specify). 15
Other (please specify) 16
Digestion Procedure for TP
APHA APHA 4500 – P B3. Perchloric Acid 17
APHA 4500 – P B4. Sulfuric-Nitric 18
APHA 4500 – P B5. Persulfate 19
USEPA US EPA 0200.2 Phosphorus - Sample Preparation 20
Other In-house method 21
Modified Standard Method 22
Other (please specify) 23
C4
SD 9.17.10
Method Codes to be used for the Results Sheet (cont .)
ANALYSIS METHOD REFERENCE METHOD DESCRIPTION CODE
Total Kjeldahl Nitrogen (TKN)
APHA APHA Part 4500 - Norg B. Macro-Kjeldahl Method 24
APHA Part 4500 - Norg C. Semi-Micro Kjeldahl Method 25
APHA Part 4500 - Norg D. Block Digestion and Flow Injection Analysis 26
USEPA USEPA 0351.1 – 0351.4 0351.1 Colorimetric/ Automated 0351.2 Colorimetric 0351.2 Semi-Automated Colorimetric 0351.3 Colorimetric/ Titrimetric 0351.4 Potentiometric
27
ESS Method 230.1: Total Phosphorus and Total Kjeldahl Nitrogen, Semi-Automated Method
28
ASTM ASTM D3590 - 11 Standard Test Methods for Total Kjeldahl Nitrogen in Water 29
ISO / CEN ISO 5663:1984 (EN 25663:1993) Water quality - Determination of Kjeldahl nitrogen - Method after mineralization with selenium
30
ISO 11905-1:1997 Water quality - Determination of nitrogen - Part 1: Method using oxidative digestion with peroxodisulfate
31
EN 12260:2003 Water quality - Determination of nitrogen -Determination of bound nitrogen (TNb), following oxidation to nitrogen oxides
32
Other Modified Standard Method 33
Discrete Analyser 34
AA / FIA 35
Test Kit, Colorimeter (HACH… specify). 36
Calculation (TN-NOx =TKN) 37
Other (please specify) 38
TKN Catalyst Mercury 39
Copper 40
Selenium 41
Sodium nitroferricyanide 42
Titanium 43
Other (please specify) 44
Continued on next page for Ammonia analysis methods.
C5
SD 9.17.10
Method Codes to be used for the Results Sheet (cont .)
ANALYSIS METHOD REFERENCE METHOD DESCRIPTION CODE
Ammonia Measurement for TKN
APHA APHA 4500 – NH3 C. Titrimetric Method 45
APHA 4500 – NH3 D. Ammonia-Selective Electrode Method 46
APHA 4500 – NH3 E. Ammonia-Selective Electrode Method Using Known Addition 47
APHA 4500 – NH3 F. Phenate Method 48
APHA 4500 – NH3 G. Automated Phenate Method 49
APHA 4500 – NH3 H. Flow Injection Analysis 50
USEPA US EPA 0351.1 – 0351.4 0351.1 Colorimetric/ Automated 0351.2 Colorimetric 0351.2 Semi-Automated Colorimetric 0351.3 Colorimetric/ Titrimetric 0351.4 Potentiometric
51
Other Modified Standard Method 52
Discrete Analyser 53
AA / FIA 54
Test Kit, Colorimeter (e.g. HACH… specify). 55
Other (please specify) 56
Method Reference Key i) APHA SM APHA “Standard Methods for the Examination of Water and Wastewater” (18, 19 20,
21, 22 Edition). (http://www.standardmethods.org/) ii) ASTM Annual Book of ASTM Standards, Vol. 11.01(2004). (http://www.astm.org) iii) CEN European Committee for Standardization. (http://www.cen.eu/cen). iv) ISO International Organization for Standardization. (http://www.iso.org). v) US EPA U.S Environmental Protection Agency.
(http://www.epa.gov/osa/fem/methcollectns.htm), (http://www.epa.gov/greatlakes/lmmb/methods).
SD 9.17.10
Please note:Where possible, proficiency testing samples should be treated as a routine
*Approximate temperature of samples upon receipt:
ANALYSIS
Sample PTA 1 Total Kjeldahl Nitrogen (TKN)Total Phosphorus (TP)
Sample PTA 2 Total Kjeldahl Nitrogen (TKN)Total Phosphorus (TP)
Sample PTA 3 Total Kjeldahl Nitrogen (TKN)Total Phosphorus (TP)
i) For
ii) Report results for the diluted sample.
iii) Report results using three significant figures.iv) Report results in
v) Do not correct results for recovery.
vi) MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in mg/L
DATE:
INSTRUCT WATERS PROF TEST PROG 186
SD 9.17.10
Please note: Where possible, proficiency testing samples should be treated as a routine
*Approximate temperature of samples upon receipt:
ANALYSIS
Sample PTA 1 (Bottle diluted x100)
Kjeldahl Nitrogen (TKN)
Phosphorus (TP)
Sample PTA 2 (Bottle diluted x100)
Total Kjeldahl Nitrogen (TKN)
Phosphorus (TP)
Sample PTA 3 (Bottle diluted x100)
Total Kjeldahl Nitrogen (TKN)
Phosphorus (TP)
For each prepared sample only a single result is requested.
Report results for the diluted sample.
Report results using three significant figures.Report results in
Do not correct results for recovery.
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in mg/L, using the same number of decimal places as for the result.
DATE: ______________________
Return results Delfina MihailaProficiency Testing AustraliaPO Box 7507 SILVERWATER NSW 2128 AUSTRALIA
INSTRUCT WATERS PROF TEST PROG 186
PROFICIENCY
WATERS PROFICIENCY TESTING PROGRAM
Total Kjeldahl Nitrogen, Total Phosphorus
Where possible, proficiency testing samples should be treated as a routine
*Approximate temperature of samples upon receipt:
Result (mg/L)
(Bottle diluted x100)
(Bottle diluted x100)
(Bottle diluted x100)
prepared sample only a single result is requested.
Report results for the diluted sample.
Report results using three significant figures.Report results in milligrams per litre (mg/L).
Do not correct results for recovery.
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in , using the same number of decimal places as for the result.
______________________
Return results NO LATEDelfina Mihaila Proficiency Testing AustraliaPO Box 7507 SILVERWATER NSW 2128 AUSTRALIA
INSTRUCT WATERS PROF TEST PROG 186
PROFICIENCY
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Total Kjeldahl Nitrogen, Total PhosphorusSEPTEMBER, 2015
RESULTS SHEET
Where possible, proficiency testing samples should be treated as a routine
*Approximate temperature of samples upon receipt:
Result
±MU*(mg/L)
(Bottle diluted x100)
(Bottle diluted x100)
(Bottle diluted x100)
prepared sample only a single result is requested.
Report results for the diluted sample.
Report results using three significant figures.milligrams per litre (mg/L).
Do not correct results for recovery.
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in , using the same number of decimal places as for the result.
______________________
NO LATER THAN 2 OCTOBER 2015
Proficiency Testing Australia PO Box 7507 SILVERWATER NSW 2128
INSTRUCT WATERS PROF TEST PROG 186
C6
PROFICIENCY TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Total Kjeldahl Nitrogen, Total PhosphorusSEPTEMBER, 2015
RESULTS SHEET(mg/L)
Where possible, proficiency testing samples should be treated as a routine
*Approximate temperature of samples upon receipt:
±MU* (mg/L)
METHOD
prepared sample only a single result is requested.
Report results for the diluted sample.
Report results using three significant figures. milligrams per litre (mg/L).
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in , using the same number of decimal places as for the result.
SIGNATURE:
R THAN 2 OCTOBER 2015
PO Box 7507 Phone:SILVERWATER NSW 2128 Fax:
Email:
TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Total Kjeldahl Nitrogen, Total PhosphorusSEPTEMBER, 2015
RESULTS SHEET
Where possible, proficiency testing samples should be treated as a routine
METHOD CODE
prepared sample only a single result is requested.
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in , using the same number of decimal places as for the result.
SIGNATURE: _______________________________
R THAN 2 OCTOBER 2015 to:
Phone: +61 2 9736 8397 +61 2 9743 6664
Email: [email protected]
TESTING AUSTRALIA
WATERS PROFICIENCY TESTING PROGRAM
CHEMICAL ANALYSIS ROUND 186
Total Kjeldahl Nitrogen, Total Phosphorus
Where possible, proficiency testing samples should be treated as a routine laboratory sample.
Laboratory Code
DIGESTION
or CATALYST
CODE
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in , using the same number of decimal places as for the result.
_______________________________
+61 2 9736 8397 +61 2 9743 6664 [email protected]
laboratory sample.
Laboratory Code
DIGESTION
CATALYST CODE
FINAL AMMONIA METHOD
CODE
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in
_______________________________
laboratory sample.
FINAL AMMONIA METHOD
CODE
MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in
_______________________________
SD 9.17.10
- End of Report -