Report No . 899 Waters Proficiency Testing Round No. 174 ... · Total Recoverable Oil and Grease...

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- Total Recoverable Oil and Grease

PTA wishes to gratefully acknowledge the technical assistance provided for this program by Mrs R Ryan, Global Proficiency Ltd (New Zealand). Also our thanks go to Global Proficiency Ltd (New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.

9.17.09

Waters Proficiency Testing

Total Recoverable Oil and Grease

PTA wishes to gratefully acknowledge the technical assistance provided for this program by Mrs R Ryan, Global Proficiency Ltd (New Zealand). Also our thanks go to Global Proficiency

(New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution of the samples.

PO Box 7507

Report No


Round



(New Zealand) and to Global Proficiency Pty Ltd (Australia) for the supply and distribution

© Copyright

PO Box 7507

Report No


Round


March 2015

Acknowledgments



© Copyright Proficiency Testing Australia

PO Box 7507 SILVERWATER

Report No


Round No.


March 2015

Acknowledgments



Proficiency Testing Australia

SILVERWATER NSW

Report No . 899


o. 174


March 2015

Acknowledgments



Proficiency Testing Australia

NSW 2128

899


174




Proficiency Testing Australia , 2015

2128, Australia





2015

, Australia

Total Recoverable Oil and Grease -



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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 ................................................................................................................. 12

6. Reference ........................................................................................................................ 12

APPENDIX A – Results and Data Analysis

Total Recoverable Oil and Grease Sample PTA 1 ................................................................ A1


APPENDIX B – Sample Homogeneity and Stability

Homogeneity and Stability Testing ........................................................................................ B1

APPENDIX C – Documentation

Instructions to Participants .................................................................................................... C1

Method Codes ....................................................................................................................... C3

Results Sheet ........................................................................................................................ C4

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1. Foreword

This report summarises the results of a proficiency testing program on the determination of Total Recoverable Oil and Grease in waters. This is round 174 in a planned series of programs involving the analysis of chemical and physical parameters of waters. The exercise was conducted in December 2014 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 Mrs R Ryan, 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.

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 two glass vials (labelled PTA 1 and PTA 2) for

analysis of Total Recoverable Oil and Grease. 2.4 A total of 50 laboratories received samples, comprising:

- 29 Australian participants; and

- 21 overseas participants, including:

- Brunei Darussalam (1), Indonesia (2), Malaysia (8), New Zealand (2), Nigeria (3), Papua New Guinea (2), Qatar (1), Thailand (1), Vietnam (1).

Of these 50 laboratories, nine 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).

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 sample are presented in Appendix A. 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.

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2.7 A tabulated listing of laboratories (by code number) identified as having outlier results can be found on page 12.

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 sample 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 results are considered to be questionable results.

Each determination was examined for outliers with all methods pooled. The table on

page 12 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 decimal places) 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. Weight checks were undertaken on all samples to ensure that the variability on doping concentrations was less than 1% (see Appendix B). Dope concentrations presented in Table 1 illustrate the average oil and grease sample weight and the 95% confidence interval for weight variation at manufacturing, expressed as ± 2SD (standard deviation). Sample PTA 1 was prepared from high purity mineral oil and stearic acid which has a low viscosity in distilled water. Sample PTA 2 was prepared from a mixture of vegetable oil, anhydrous milk fat and stearic acid in distilled water. Samples were prepared as concentrates (~30 mL) equivalent to 1 litre of wastewater, packaged in Teflon capped glass vials and preserved with acid to pH 2. 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. As the assigned value for each sample in this program is the median of the results submitted by the participants, the uncertainty of the median for each sample has been calculated and is presented in Table 1 below. Table 1. Comparison of expected levels (dope concentration) and proficiency medians. The values of the calculated uncertainty of the median are also presented.

Analysis Sample

Dope Concentration

± 2SD (mg/L)

Median (mg/L)

Uncertainty of the median

(mg/L)

Total Recoverable Oil

and Grease

PTA 1 74.9 ± 0.4 71.70 1.45

PTA 2 46.2 ± 0.3 44.00 1.00

The median concentrations indicate that on average 96% of Total Recoverable Oil and Grease was recovered for sample PTA 1 and 95% for sample PTA 2.

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4.2 Analysis of Round 174 Results Table 2 compares the Total Recoverable Oil and Grease median and robust CV from this round to those obtained in previous PTA rounds. Table 2. Comparison of current round variability and proficiency medians of Total Recoverable Oil and Grease testing with the results of the previous two rounds.

Round Sample Median (mg/L) Robust CV (%) Participants

This study PTA 1 71.70 10.3 41

PTA 2 44.00 11.4 39

Report 847 PTA 1 31.20 12.2 46

PTA 2 59.50 10.0 45

Report 799 PTA 1 20.80 17.1 48

PTA 2 85.10 14.1 48 Overall, the performance of participants in this round was good. Robust CVs of less than 12% were observed, which were comparable to those seen in the last round. The contribution of sample variation to this CV was negligible (< 1%), based on sample manufacturing procedures (see Appendix B). Bias / Accuracy The Total Recoverable Oil and Grease testing was successfully performed, with satisfactory results (|z-score| ≤ 2.0) ranging between 56.9 – 86.5 mg/L for sample PTA 1 and 34.0 – 54.0 mg/L for sample PTA 2. Out of 41 results submitted for sample PTA 1 and 39 results for sample PTA 2, two questionable results (2.0 < |z-score| < 3.0) were reported for sample PTA 1 (laboratories 220 and 368) and two questionable results were reported for sample PTA 2 (laboratories 210 and 494). Seven outlier results (|z-score| ≥ 3.0) were obtained for sample PTA 1, requiring follow-up action by laboratories 210, 375, 382, 474, 506, 634 and 674. Seven outlier results were also obtained for sample PTA 2, requiring follow-up action by laboratories 128, 375, 382, 474, 506, 587 and 634. The data sets for samples PTA 1 and PTA 2 formed an approximately normal distribution with no significant bias attributable to any one method (Figures 1 and 2). The method most frequently used for Total Recoverable Oil and Grease testing in this round was APHA 5520 B (Liquid-Liquid, Partition-Gravimetric Method), which was used by approximately 51% of participants.

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Figure 1. Spread of results for Total Recoverable Oil and Grease testing of sample PTA 1, with a median of 71.70 mg/L.

Figure 2. Spread of results for Total Recoverable Oil and Grease testing of sample PTA 2, with a median of 44.00 mg/L.

0

4

8

12

16

20

30 37.5 45 52.5 60 67.5 75 82.5 90 97.5 105 112.5 120 127.5

Fre

quen

cy

Results (mg/L)

Total Recoverable Oil and Grease - Sample PTA 1

APHA 5520 B

APHA 5520 G

US EPA 1664A

APHA 5520 C

ASTM D 7066-04

ASTM D 3921-96

APHA 5520 D

US EPA 1664A, Other

Other

>

0

2

4

6

8

10

12

14

7 12 17 22 27 32 37 42 47 52 57 62 67 72

Fre

quen

cy

Results (mg/L)


APHA 5520 B

APHA 5520 G

US EPA 1664A

APHA 5520 C

ASTM D 7066-04

ASTM D 3921-96

APHA 5520 D

US EPA 1664A, Other

Other

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Measurement Uncertainty (MU) The MU reported by participants can be seen in Figures 3 and 4. Out of 41 participants for sample PTA 1 and 39 participants for sample PTA 2, 28 (68%) and 27 (69%) submitted MU information for samples PTA 1 and PTA 2, respectively. Many of the stated MUs did not accurately reflect the difference between the median and the participant’s result for these proficiency samples.

Figure 3. MU for Total Recoverable Oil and Grease testing of sample PTA 1, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 15.79 mg/L in this round, shown as a dashed line.

0

1

2

3

4

5

6

7

8

0 2 4 6 8 10 12 14 16 18 20 22 24 26

Fre

quen

cy

Measurement Uncertainty (mg/L)

Total Recoverable Oil and Grease ± MU - Sample PTA 1

APHA 5520 B

APHA 5520 G

US EPA 1664A

APHA 5520 C

ASTM D 7066-04

APHA 5520 D

US EPA 1664A, Other

Other

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Figure 4. MU for Total Recoverable Oil and Grease testing of sample PTA 2, as reported by participants, compared with 95% confidence interval for overall reproducibility, ± 10.20 mg/L in this round, shown as a dashed line. A t-test of all the results (outliers removed), indicated that the overall reproducibility for Total Recoverable Oil and Grease testing was 71.70 ± 15.79 mg/L for sample PTA 1 and 44.00 ± 10.20 mg/L for sample PTA 2 (95% CI). Laboratories 128, 210, 220, 368, 375, 382, 466, 494, 506, 545, 587, 588, 634 and 674 may wish to re-examine their MU calculations, as their result was further from the median than their stated MU at least for one of the samples tested, as shown in Figures 5 and 6 below.

0

1

2

3

4

5

6

0 1.5 3 4.5 6 7.5 9 10.5 12 13.5 15 16.5 18 19.5

Fre

quen

cy

Measurement Uncertainty (mg/L)

Total Recoverable Oil and Grease ± MU - Sample PTA 2

APHA 5520 B

APHA 5520 G

US EPA 1664A

APHA 5520 C

ASTM D 7066-04

APHA 5520 D

US EPA 1664A, Other

Other

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Results of sam

ple PT

A 1, including M

U, com

pared to the m

edian

Total R

ecoverable Oil and G

rease - Sam

ple PT

A 1

Figure 5. Total Recoverable Oil and Grease - Results of sample PTA 1, including MU, compared to themedian.

20

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50

60

70

80

90

100

110

120

130

140

150

16012

5

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128

144

210

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286

300

329

368

375

382

398

410

430

466

494

506

531

545

568

587

588

596

629

634

636

674

Re

sults

(mg/

L)

Laboratory Code


Result ± MU Median Uncertainty of the Median

10

SD

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Results of sam

ple PT

A 2, including M

U, com

pared to the m

edian

Total R


rease - Sam

ple PT

A 2

Figure 6. Total Recoverable Oil and Grease - Results of sample PTA 2, including MU, compared to themedian.

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Re

sults

(mg/

L)

Laboratory Code


Result ± MU Median Uncertainty of the Median

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4.3 Analysis of Results by Method Groups

Further analysis of results by method groups was undertaken to provide specific information on individual method performance. In order for methods to be grouped for analysis, PTA requires at least 11 sets of results from the same method group. For methods other than APHA 5520 B presented below, there were less than 11 results submitted, therefore reliable conclusions cannot be drawn from analysing them separately on this occasion. The method APHA 5520 B (Liquid-Liquid, Partition-Gravimetric Method - method code 1) was the most frequently employed method for analysing Total Recoverable Oil and Grease in this round. Out of 41 results submitted for sample PTA 1, 21 laboratories indicated the use of this method. For sample PTA 2, out of 39 results, 20 laboratories used APHA 5520 B. Table 3 below presents the median, uncertainty of the median and robust CV for Total Recoverable Oil and Grease results obtained by method 1 (APHA 5520 B). Table 3. Variability and proficiency medians of Total Recoverable Oil and Grease results obtained by method 1 (APHA 5520 B).

Analysis Sample Participants Median ±

Uncertainty of the Median (mg/L)

Robust CV (%)

Total Recoverable

Oil and Grease

PTA 1 21 70.00 ± 1.34 7.0

PTA 2 20 44.55 ± 1.12 9.0

The CVs seen in Table 3 for laboratories using method APHA 5520 B were slightly smaller than those of the overall dataset (CV = 10.3% and 11.4% for samples PTA 1 and PTA 2, respectively). Applying a coverage factor of 2 (95% CI) to the robust CV for this method indicates an approximate reproducibility for APHA 5520 B method of 14.0-18.0%. APHA method 5520 B (22nd Ed) states an average recovery of 93% and precision (%RSD) of 8.7%, determined from an interlaboratory method validation study. The average recoveries determined by this method in round 174 (93% for sample PTA 1 and 96% for sample PTA 2) are in good agreement with those determined by APHA. The robust CVs of 7.0% for sample PTA 1 and 9.0% for sample PTA 2 observed in this study are also in good agreement with the precision stated by APHA (8.7% RSD).

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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 sample tested.

Lab Code


PTA 1 PTA 2

128 §

210 §

375 § §

382 § §

474 § §

506 § §

587 §

634 § §

674 §

Note: 1. A “§” indicates the occurrence of a z-score outlier result (i.e. those results for which

|z-score| ≥ 3.0). 6. Reference

[1] Guide to Proficiency Testing Australia, 2014 (This document can be found on the PTA website, www.pta.asn.au)

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APPENDIX A

Results and Data Analysis Total Recoverable Oil and Grease Sample PTA 1 ................................................................ A1


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Total Recoverable Oil and Grease Results

Samples PTA 1 and PTA 2

A1

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Results by Laboratory Code

Lab Code

Sample PTA 1

Result ± MU1 (mg/L)

Robust z-score2

Method Code3

123 70.7 # -0.13 1 125 71.8 ± 15 0.01 9 126 69.0 ± 7.3 -0.36 9 128 74.3 ± 17.2 0.35 1 144 72.9 ± 14.8 0.16 1 210 140.8 ± 15 9.32 § 5 220 89.7 ± 10.8 2.43 5 286 74 ± 14.8 0.31 3 300 75.0 ± 15.7 0.45 5 325 65.0 # -0.90 1 329 64.0 ± 12.8 -1.04 9 342 69.7 # -0.27 1 362 63.3 # -1.13 1 368 52 ± 5 -2.66 9 375 43.6 ± 2.2 -3.79 § 1 382 41.0 ± 1.0 -4.14 § 2 393 71.7 # 0.00 1 398 72.6 ± 14.5 0.12 1 408 71.8 # 0.01 1 410 75 ± 10 0.45 3 430 83.9 ± 21.9 1.65 3 466 86.0 ± 6.2 1.93 5 474 48 # -3.20 § 6 487 57.8 # -1.88 1 492 73.2 # 0.20 1 494 83.2 ± 5.0 1.55 2 498 70 # -0.23 1 506 107.6 ± 2 4.84 § 10 519 75.0 # 0.45 1 531 69.4 ± 14 -0.31 1 545 66 ± 1.5 -0.77 1 552 66.5 # -0.70 1

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 (page C3) for method code descriptions.

A2

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Total Recoverable Oil and Grease - cont.


Lab Code

Sample PTA 1


Robust z-score2

Method Code3

568 79.1 ± 15.3 1.00 1 587 66.5 ± 13.3 -0.70 3, 10 588 78.6 ± 2.2 0.93 5 596 72 ± 7.2 0.04 1 621 64.5 # -0.97 2 629 69 ± 8.6 -0.36 1 634 30.1 ± 0.3 -5.61 § 4 636 61.2 ± 10.6 -1.42 1 674 95.0 ± 9.5 3.14 § 4

No of Results: 41

Median: 71.70 Normalised

IQR: 7.41

Uncertainty of the Median:

1.45

Robust CV: 10.3%

Minimum: 30.1

Maximum: 140.8

Range: 110.7 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.


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Total Recoverable Oil and Grease - Sample PTA 1 - R obust Z-Scores

Ordered R

obust Z-S

core Charts

Total R


rease - Sam

ple PT

A 1

A3

Robust Z-Scores

634 38

2 375 47

4 368 48

7 636

362

329

621

325

545

552

587 12

6

629

531

342

498

123

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scor

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ore

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A4

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Lab Code

Sample PTA 2


Robust z-score2

Method Code3

123 47.7 # 0.74 1 125 40.2 ± 8.5 -0.76 9 126 40.3 ± 4.2 -0.74 9 128 25.3 ± 5.8 -3.74 § 1 144 42.2 ± 8.6 -0.36 1 210 55.5 ± 5 2.30 5 220 44.0 ± 5.3 0.00 5 286 46 ± 9.2 0.40 3 325 46.6 # 0.52 1 329 42.0 ± 8.4 -0.40 9 342 44.3 # 0.06 1 368 37 ± 4 -1.40 9 375 21.9 ± 1.1 -4.42 § 1 382 24.0 ± 1.0 -4.00 § 2 393 44.9 # 0.18 1 398 45.2 ± 9.0 0.24 1 408 44.8 # 0.16 1 410 48 ± 10 0.80 3 430 50.1 ± 13.1 1.22 3 466 36.7 ± 2.6 -1.46 5 474 72 # 5.60 § 6 487 35.8 # -1.64 1 492 49.6 # 1.12 1 494 57.2 ± 5.0 2.64 2 498 46 # 0.40 1 506 7.2 ± 2 -7.35 § 10 519 45.3 # 0.26 1 531 41.1 ± 8 -0.58 1 545 40 ± 1.4 -0.80 1 552 40.1 # -0.78 1 568 47.2 ± 9.1 0.64 1 587 68.0 ± 13.6 4.80 § 3, 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.


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Total Recoverable Oil and Grease - cont.


Lab Code

Sample PTA 2


Robust z-score2

Method Code3

588 36.8 ± 1.0 -1.44 5 596 45 ± 4.5 0.20 1 621 39.4 # -0.92 2 629 42 ± 5.2 -0.40 1 634 22.8 ± 0.3 -4.24 § 4 636 39.7 ± 6.9 -0.86 1 674 44.0 ± 4.4 0.00 4

No of Results: 39

Median: 44.00 Normalised

IQR: 5.00

Uncertainty of the Median:

1.00

Robust CV: 11.4%

Minimum: 7.2

Maximum: 72

Range: 64.8 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.


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Total Recoverable Oil and Grease - Sample PTA 2 - R obust Z-Scores

Ordered R

obust Z-S

core Charts

Total R


rease - Sam

ple PT

A 2

A6

Robust Z-Scores

506 37

5

634

382

128

487

466

588

368 62

1

636

545

552

125

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531

329

629

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220

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APPENDIX B

Sample Homogeneity and Stability

Homogeneity and Stability Testing ........................................................................................ B1

B1

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Homogeneity and Stability Testing Samples for this program were obtained from Global Proficiency Ltd, New Zealand. As such, all samples are subjected to rigorous stability and homogeneity testing. All samples underwent quality control weight checks to ensure a consistent mass of oil and grease was delivered to each vial. Sample PTA 1 contained 74.92 ± 0.38 mg/L (95% CI) of mineral oil and stearic acid, and sample PTA 2 contained 46.23 ± 0.30 mg/L (95% CI) of a mixture of vegetable oil, anhydrous milk fat and stearic acid. Results have been displayed in Table B1 below. Table B1. Homogeneity weight checks during sample manufacture.

PTA 1 PTA 1 PTA 2 PTA 2

No. Wgt (g) No. Wgt (g) No. Wgt (g) No. Wgt (g)

1 0.0748 41 0.0746 1 0.0461 41 0.0460

2 0.0749 42 0.0750 2 0.0463 42 0.0460

3 0.0751 43 0.0752 3 0.0464 43 0.0461

4 0.0748 44 0.0746 4 0.0464 44 0.0464

5 0.0746 45 0.0750 5 0.0461 45 0.0463

6 0.0751 46 0.0748 6 0.0460 46 0.0464

7 0.0751 47 0.0750 7 0.0461 47 0.0461

8 0.0747 48 0.0752 8 0.0462 48 0.0464

9 0.0751 49 0.0746 9 0.0462 49 0.0460

10 0.0751 50 0.0747 10 0.0462 50 0.0464

11 0.0749 51 0.0748 11 0.0464 51 0.0462

12 0.0748 52 0.0749 12 0.0461 52 0.0462

13 0.0751 53 0.0748 13 0.0463 53 0.0462

14 0.0749 54 0.0751 14 0.0464 54 0.0462

15 0.0751 55 0.0750 15 0.0462 55 0.0461

16 0.0746 56 0.0748 16 0.0464 56 0.0460

17 0.0747 57 0.0750 17 0.0462 57 0.0464

18 0.0750 58 0.0752 18 0.0462 58 0.0465

19 0.0748 59 0.0750 19 0.0463 59 0.0460

20 0.0751 60 0.0746 20 0.0464 60 0.0460

21 0.0746 61 0.0749 21 0.0463 61 0.0464

22 0.0749 62 0.0751 22 0.0463 62 0.0461

23 0.0749 63 0.0750 23 0.0462

24 0.0752 64 0.0752 24 0.0462

25 0.0751 65 0.0750 25 0.0461

26 0.0751 66 0.0752 26 0.0464

27 0.0748 67 0.0747 27 0.0464

28 0.0749 68 0.0748 28 0.0464

29 0.0749 69 0.0750 29 0.0463

30 0.0751 70 0.0752 30 0.0463

31 0.0751 31 0.0460

32 0.0748 32 0.0460

33 0.0746 33 0.0464

34 0.0747 34 0.0463

35 0.0748 35 0.0462

36 0.0751 36 0.0461

37 0.0747 37 0.0464

38 0.0752 38 0.0460

39 0.0747 39 0.0462

40 0.0747 40 0.0464

Mean 0.0749 Mean 0.0462

Stdev 0.0002 Stdev 0.0001

CV 0.26% CV 0.32%

B2

SD 9.17.09

A random selection of ten samples was chosen from samples PTA 1 for homogeneity and stability testing. Seven of these were stored chilled at 4ºC and the remaining three were subjected to 35ºC for three days, for an accelerated ageing stability trial. Samples were then analysed for Oil and Grease by Hill Laboratories, New Zealand, using method APHA 5520 D (modified) 22nd Ed. 2012. All stability samples showed no increased variability when compared to chilled samples (see Table B2). Samples PTA 2 were also tested to confirm the levels were within the expected range. Two samples were randomly selected, stored chilled in the same conditions as the homogeneity samples and subjected to a verification testing by Hill Laboratories, New Zealand. Homogeneity and stability characteristics were assumed to be similar to samples PTA 1, based on identical manufacturing procedure and sample handling. Table B2. Homogeneity and stability testing of samples.

Round PTA 161

Sample ID

Oil and Grease (mg/L)

Samples PTA 1 Samples PTA 2 Test Quality Control Test Quality Control

Homogeneity H1 73.6 75.1 41.7 46.3 H2 73.3 74.7 44.5 46.0 H3 72.7 74.6 H4 74.4 74.9 H5 75.3 74.8 H6 73.9 75.0 H7 75.2 75.1

Stability S1 74.2 74.8 S2 75.5 75.1 S3 74.6 75.2

Median 74.8 75.0

CV 1.0% 0.3% 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.

SD 9.17.09

APPENDIX C

Documentation

Instructions to Participants .................................................................................................... C1

Method Codes ....................................................................................................................... C3

Results Sheet ........................................................................................................................ C4

SD 9.17.09

CHEMICAL ANALYSIS ROUND 174 Total Recoverable Oil and Grease

**Please record (on the Results Sheet) the approximate tempe rature of the

Please note the following before commencing the analysis of the samples. 1. Samples

i)

ii) Please Note:laboratory sample.

2. Sample Preparation

Caution:

i) ii) iii) iv)

v)

Note: Please treat as “unknown oil”.

9.17.09

CHEMICAL ANALYSIS ROUND 174



Please note the following before commencing the analysis of the samples.

Samples

Two glass vials with PTFE capProficiency Ltd. The vials contain oil and grease (in water) in per litre (mg/L). These have been acid preserved and should be refrigerated until ready to test.

The sample must be thoroughly mixed prior to analysis.

Please Note: laboratory sample.

Sample Preparation

Caution: Analysis must begin immediately after vial is opened.

Adjust vial temperature to 20º C.

Record vial ID number.

Shake the vial prior to opening.

Each vial is ready to test and is a concentrate equivalent to 1 Litre (1L) of sample, the oil and grease have been weighed into the vial as such. Please 1000mL for any volume calculations, do not try to measure the volumvial (20ml in 40 ml vial is not applicable for calculations)

Test according to your normal procedures.

Please treat as “unknown oil”.

PROFICIENCY TESTING AUSTRALIA

WATERS PROFICIENCY TESTING PROGRAM



INSTRUCTIONS TO PARTICIPANTS



Two glass vials with PTFE capProficiency Ltd. The vials contain oil and grease (in water) in per litre (mg/L). These have been acid preserved and should be refrigerated until ready to


Where possible, proficiency testing samples should be trealaboratory sample.

Sample Preparation

Analysis must begin immediately after vial is opened.




Each vial is ready to test and is a concentrate equivalent to 1 Litre (1L) of sample, the oil and grease have been weighed into the vial as such. Please

for any volume calculations, do not try to measure the volumvial (20ml in 40 ml vial is not applicable for calculations)










Two glass vials with PTFE cap-liner, labelled PTA 1 and PTA 2, supplied by Global Proficiency Ltd. The vials contain oil and grease (in water) in per litre (mg/L). These have been acid preserved and should be refrigerated until ready to


Where possible, proficiency testing samples should be trea









C1




**Please record (on the Results Sheet) the approximate tempe rature of the receipt**


liner, labelled PTA 1 and PTA 2, supplied by Global Proficiency Ltd. The vials contain oil and grease (in water) in per litre (mg/L). These have been acid preserved and should be refrigerated until ready to












liner, labelled PTA 1 and PTA 2, supplied by Global Proficiency Ltd. The vials contain oil and grease (in water) in per litre (mg/L). These have been acid preserved and should be refrigerated until ready to




Each vial is ready to test and is a concentrate equivalent to 1 Litre (1L) of sample, the oil and grease have been weighed into the vial as such. Please regard the water volume as exactly

for any volume calculations, do not try to measure the volumvial (20ml in 40 ml vial is not applicable for calculations).






liner, labelled PTA 1 and PTA 2, supplied by Global Proficiency Ltd. The vials contain oil and grease (in water) in the range of 10per litre (mg/L). These have been acid preserved and should be refrigerated until ready to


Each vial is ready to test and is a concentrate equivalent to 1 Litre (1L) of sample, the oil and regard the water volume as exactly

for any volume calculations, do not try to measure the volum

DECEMBER, 2014

**Please record (on the Results Sheet) the approximate tempe rature of the samples upon

liner, labelled PTA 1 and PTA 2, supplied by Global the range of 10-100 milligrams

per litre (mg/L). These have been acid preserved and should be refrigerated until ready to

Where possible, proficiency testing samples should be treated as a routine


for any volume calculations, do not try to measure the volume of the water in the

DECEMBER, 2014

samples upon

liner, labelled PTA 1 and PTA 2, supplied by Global 100 milligrams

per litre (mg/L). These have been acid preserved and should be refrigerated until ready to

ted as a routine


e of the water in the

C2

SD 9.17.09

3. Tests Requested

i) Total Recoverable Oil and Grease. 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 safety glasses, gloves, and fume hoods, where appropriate during the determinations, is recommended.

5. Reporting

i) Report results using one decimal place.

ii) Report results in milligrams per litre (mg/L) - i.e., the total mg extracted/sample treated as 1L

for reporting.

iii) Do not correct results for recovery.

iv) In addition to reporting the results, record the method of analysis using the attached codes.

v) Laboratories are also requested to calculate and report an estimate of measurement uncertainty (MU) for each reported measurement result. All estimates of MU must be given as a 95% confidence interval (coverage factor k ≈ 2) and reported in mg/L.

6. Testing should commence as soon as possible after receiving the samples and results reported

NO LATER THAN 16 JANUARY 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 (in mg/L):

Analyte Range

Total Recoverable Oil and Grease 10 – 100 mg/L

C3

SD 9.17.09

Method Codes to be used for the Results Sheet

ANALYSIS METHOD METHOD DESCRIPTION CODE


Partition-Gravimetric

APHA 5520 B. Liquid-Liquid, Partition-Gravimetric Method

1

APHA 5520 G. Solid-Phase, Partition-Gravimetric Method 2

Hexane Extraction & Gravimetry

US EPA 1664A Oil & Grease (HEM/SGT-HEM) by extraction 3

Infrared APHA 5520 C. Partition-Infrared Method 4

ASTM D 7066-04 Standard Test Method for dimer/trimer of chlorotrifluoroethylene (S-316) Recoverable Oil and Grease and Nonpolar Material by Infrared Determination

5

ASTM D 3921-96 Standard Test Method for Oil and Grease and Petroleum Hydrocarbons in Water

6

US EPA 413.2 Oil & Grease, Total Recoverable - Spectrophot.

7

US EPA 418.1 Petroleum Hydrocarbons, Total Recoverable

8

Soxhlet Extraction APHA 5520 D. Soxhlet Extraction Method 9

Other Please specify 10

Method Reference Key i) APHA APHA “Standard Methods for the Examination of Water and Wastewater” (18,

19, 20, 21, 22 Edition) (http://www.standardmethods.org/). ii) ASTM American Society for Testing and Materials, Annual Book of ASTM Standards,

Vol. 11.01 and Vol. 11.02. iii) US EPA U.S Environmental Protection Agency.

(http://www.epa.gov/osa/fem/methcollectns.htm), (http://www.epa.gov/greatlakes/lmmb/methods).

SD 9.17.09

*Approximate temperature of samples upon receipt:


Please note:

i) For ii) Report results using one decimal place. iii) Report results in

for reporting. iv) Do not correct results for recovery. v) MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in DATE:

INSTRUCT WATERS PROF TEST PROG 174

9.17.09


ANALYSIS


Please note: Where possible, proficiency testing samples should be treated as a routine laboratory sample.

For each sample only a single result is requested.

Report results using one decimal place.

Report results in for reporting.

Do not correct results for recovery.

MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in

DATE: ______________________

Return results Delfina MihailaProficiency Testing AustraliaPO Box 7507 SILVERWATER NSW 2128 AUSTRALIA





ANALYSIS

Total Recoverable Oil

Where possible, proficiency testing samples should be treated as a routine laboratory sample.

sample only a single result is requested.


Report results in milligrams per litre (mg/L) for reporting.


MU* Laboratories Measurement Uncertainty (MU) if known for the result. Please report in mg/L.

______________________

Return results NO LATER THAN 16 JANUARY 2015 Delfina Mihaila Proficiency Testing AustraliaPO Box 7507 SILVERWATER NSW 2128 AUSTRALIA




CHEMICAL ANALYSIS ROUND


DECEMBER, 2014

RESULTS SHEET


SAMPLE PTA 1

Result (mg/L)

Where possible, proficiency testing samples should be treated as a routine laboratory



milligrams per litre (mg/L)


MU* Laboratories Measurement Uncertainty (MU) if known for the result.

______________________

NO LATER THAN 16 JANUARY 2015

Proficiency Testing Australia PO Box 7507 SILVERWATER NSW 2128


C4



CHEMICAL ANALYSIS ROUND


DECEMBER, 2014

RESULTS SHEET(mg/L)


SAMPLE PTA 1

±MU (mg/L)




milligrams per litre (mg/L) - i.e., the total mg extracted/sample treated as 1L


SIGNATURE:

NO LATER THAN 16 JANUARY 2015

PO Box 7507 Phone:SILVERWATER NSW 2128 Fax:

Email:





DECEMBER, 2014

RESULTS SHEET

SAMPLE PTA 2

Result (mg/L)



i.e., the total mg extracted/sample treated as 1L


SIGNATURE: _______________________________

NO LATER THAN 16 JANUARY 2015 to:

Phone: +61 2 9736 8397 +61 2 9743 6664

Email: [email protected]



174


Laboratory Code

SAMPLE PTA 2

Result (mg/L)

±MU (mg/L)




_______________________________

+61 2 9736 8397 +61 2 9743 6664 [email protected]

Laboratory

SAMPLE PTA 2 METHOD

CODE±MU (mg/L)




_______________________________

[email protected]

METHOD CODE



_______________________________

SD 9.17.09

- End of Report -

Report No . 899 Waters Proficiency Testing Round No. 174 ... · Total Recoverable Oil and Grease...

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