NOT CONTROLLED WHEN PRINTED. FAPAS Proficiency Test Report Pesticide Residues in Wine. June August 2011

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1 FAPAS Proficiency Test Report Pesticide Residues in Wine June August 2011 Prepared and authorised on behalf of FAPAS by Michael Knaggs, Round Co-ordinator Crown Copyright 2011 Page 1 of PT

2 PARTICIPANT LABORATORY NUMBER Participants can log in to FAPAS SecureWeb at any time to obtain their for this proficiency test. Laboratory numbers are displayed in SecureWeb next to the download link for this report. REPORT INTEGRITY Since 2006 all FAPAS reports have been distributed as Adobe Services (CDS) Adobe PDF documents [1]. Certified Document The use of Adobe CDS allows the PDF files to certify that the author of the report is FAPAS and that the document has not been altered in anyway. A blue ribbon and information bar indicates this validation when the document is opened using Adobe Reader v7 or later. Hard copies of FAPAS reports can never incorporate this level of integrity and consequently when a FAPAS report is printed a watermark, stating that printed copies are not controlled, appears on every page. End users of FAPAS reports should ensure that either the opened PDF file displays a valid FAPAS digital signature or that the content of any hard copy exactly matches the content of a PDF file that displays a valid FAPAS digital signature. Page 2 of 38

3 SUMMARY 1. The test material for FAPAS proficiency test was dispatched in June Each participant received a wine test material to be analysed for pesticide residues. From a list of 171 pesticide residues, participants had to identify and quantify those present in the test material. 2. The test material contained bifenthrin, iprodione, iprovalicarb and phosalone. For each analyte, an assigned value (x a ) was determined. In conjunction with the standard deviation for proficiency (σ p ), a z-score for each result was calculated. 3. Results for this proficiency test are summarised as follows: analyte assigned value, x a µg/kg number of scores, total number % z 2 z 2 of scores bifenthrin iprodione iprovalicarb phosalone Surplus test materials are available for sale, see APPENDIX II. 5. Whereas this report has been produced in good faith and in accordance with best industry practice, neither The Food and Environment Research Agency nor the Secretary of State for Environment, Food and Rural Affairs accepts any liability whatsoever as to the application or use of the information contained therein. Page 3 of 38

4 CONTENTS 1. INTRODUCTION Proficiency Testing 5 2. TEST MATERIAL Preparation Homogeneity Dispatch 5 3. RESULTS 5 4. STATISTICAL EVALUATION OF RESULTS Calculation of the Assigned Value, x a Standard Deviation for Proficiency, σ p Individual z-scores 7 5. ASSESSMENT OF SCORES 7 6. REFERENCES 8 TABLES Table 1: Results and z-scores for Bifenthrin and Iprodione 9 Table 2: Results and z-scores for Iprovalicarb and Phosalone 10 Table 3: Participants Comments 11 Table 4: Assigned Values and Standard Deviations for Proficiency 11 Table 5: Number and Percentage of z-scores where z 2 11 FIGURES Figure 1: z-scores for Bifenthrin 12 Figure 2: z-scores for Iprodione 13 Figure 3: z-scores for Iprovalicarb 14 Figure 4: z-scores for Phosalone 15 APPENDICES APPENDIX I: Analytical Methods Used by Participants 16 APPENDIX II: FAPAS SecureWeb, Reports and Protocol 38 Page 4 of 38

5 1. INTRODUCTION 1.1. Proficiency Testing Proficiency testing aims to provide an independent assessment of the competence of participating laboratories. Together with the use of validated methods, proficiency testing is an essential element of laboratory quality assurance. Further details of the FAPAS proficiency testing scheme are available in our protocols [2, 3]. 2. TEST MATERIAL 2.1. Preparation Preparation of the samples for this proficiency test was sub-contracted to a laboratory meeting the quality requirements of the scheme s accreditation to ISO Organic wine was obtained from a local supplier. The wine was combined in a large container. A sample of the organic wine was screened for the presence of incurred pesticide residues. No residues were found above 30 µg/kg. The organic wine was split into two batches: one was used to prepare the blank test material, the other to produce the spiked test material. The following pesticides were spiked into the spiked test material: bifenthrin, iprodione, iprovalicarb and phosalone. Samples were stored at +4 o C until dispatch Homogeneity To test for homogeneity, randomly selected test materials were analysed in duplicate. Testing was sub-contracted to a laboratory meeting the quality requirements of the scheme s accreditation to ISO These data showed sufficient homogeneity and were not included in the subsequent calculation of the assigned values Dispatch The start date was 23 June Test materials were sent to 33 participants. 3. RESULTS The instructions for reporting results were as follows: Determine the level of pesticide residues present in the test material, in µg/kg, as received, uncorrected for recovery, together with the percentage recovery and limit of quantification (LoQ). Page 5 of 38

6 All pesticide residues are to be reported as the parent compound only, unless specified otherwise on the results form. Results were submitted by 28 participants (85%) before the closing date for this test, 4 August Each participant was given a, assigned in order of receipt of results. The reported analyte concentrations are given in Table 1 for bifenthrin and iprodione and Table 2 for iprovalicarb and phosalone. If a participant analysed for a pesticide residue that was in the test material, but did not identify it, and their limit of quantification was below the level needed for a z-score of -2.0, they were assessed as if their result was zero. Participants comments are given in Table 3. No additional pesticides were reported by participants. The analytical methods used by each participant are summarised in APPENDIX I. 4. STATISTICAL EVALUATION OF RESULTS The results submitted by participants were statistically analysed in order to provide an assigned value for each analyte. The assigned values were then used in combination with the standard deviation for proficiency, σ p, to calculate a z-score for each result. The procedure follows that recommended in the IUPAC International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories [4]. Further details on the procedure followed can be found in the relevant protocols [2, 3] Calculation of the Assigned Value, x a The assigned value, x a, was set as the consensus of the results submitted by participants. The following results were excluded from the calculation of the assigned value: i) results reported as approximately 10, 100 or 1000 greater or smaller than the majority of submitted results (as these were considered to be reporting errors), ii) results where no percentage recovery was reported, iii) results whose recovery was outside the range %, [5] iv) results where no limit of quantification was reported, For all residues, this procedure was straightforward and the robust mean was chosen as the assigned value. The assigned values for all analytes are shown in Table Standard Deviation for Proficiency, σ p The standard deviation for proficiency, σ p, was set at a value that reflects best practice for the analyses in question. For all residues, σ p was derived from the appropriate form of the Horwitz equation [6]. The values for σ p used to calculate z-scores from the reported results of this test are given in Table 4. Page 6 of 38

7 4.3. Individual z-scores Participants z-scores were calculated as: ( x z = σ p x a ) where x = the participant s reported result, x a = the assigned value and σ p = the standard deviation for proficiency. Participants z-scores are given in Table 1 for bifenthrin and iprodione and in Table 2 for iprovalicarb and phosalone and shown as histograms in Figures 1 4. It is possible for the z-scores published in this report to differ slightly from the z-score that can be calculated using the formula given above. These differences arise from the necessary rounding of the actual assigned values and standard deviations for proficiency prior to their publication in Table 4. The number and percentage of z-scores in the range -2 z 2 for all analytes are given in Table ASSESSMENT OF SCORES In normal circumstances, over time, about 95% of z-scores will lie in the range -2 z 2. Occasional scores in the range 2 < z <3 are to be expected, at a rate of 1 in 20. Whether or not such scores are of importance can only be decided by considering them in the context of the other scores obtained by that laboratory. Scores where z >3 are to be expected at a rate of about 1 in 300. Given this rarity, such z-scores very strongly indicate that the result is not fit-for-purpose and almost certainly requires investigation. The consideration of a set or sequence of z-scores over time provides more useful information than a single z-score. Examples of suitable methods of comparison are provided in the IUPAC International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories [4]. Page 7 of 38

8 6. REFERENCES 1 Adobe Certified Document Services accessed 24/05/ FAPAS, 2010, Protocol for Proficiency Testing Schemes, Part 1 Common Principles, Version 2, Issued December FAPAS, 2009, Protocol for Proficiency Testing Schemes, Part 2 FAPAS, Revision 2009, Version 1, Issued November Thompson, M., Ellison, S.L.R. and Wood, R., 2006, The International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories, Pure Appl. Chem., 78, No. 1, Pihlström, T (Co-ordinator), 2010, Method Validation and Quality Control Procedures for Pesticide Residues Analysis in Food and Feed, Document No. SANCO/10684/ Thompson, M., 2000, Recent trends in inter-laboratory precision at ppb and sub-ppb concentrations in relation to fitness for purpose criteria in proficiency testing, Analyst, 125, Page 8 of 38

9 Table 1: laboratory number Results and z-scores for Bifenthrin and Iprodione analyte bifenthrin assigned value 123 µg/kg iprodione assigned value 110 µg/kg result recovery loq z-score result recovery loq z-score µg/kg % µg/kg µg/kg % µg/kg 001 # # 002 # # # no recovery data no recovery data NQ not quantitated NQ z-scores outside z >2 are shown in bold, see Section 5 loq = limit of quantification # = pesticide residue not analysed for NQ = identified, not quantified Page 9 of 38

10 Table 2: laboratory number Results and z-scores for Iprovalicarb and Phosalone analyte iprovalicarb assigned value 138 µg/kg phosalone assigned value 83.3 µg/kg result recovery loq z-score result recovery loq z-score µg/kg % µg/kg µg/kg % µg/kg # 002 # # # # 007 # # # # # # # # # NQ z-scores outside z >2 are shown in bold, see Section 5 # = pesticide residue not analysed for loq = limit of quantification Page 10 of 38

11 Table 3: Participants Comments participant number comments 26 Iprovalicarb result is the sum of its isomers (Iprovalicarb I and Iprovalicarb II); Bifenthrin and Phosalone were detected, but not quantified comments are as submitted by participants Table 4: Assigned Values and Standard Deviations for Proficiency analyte data points, n assigned value, x a, µg/kg uncertainty, u standard deviation for proficiency, σ p, µg/kg bifenthrin Horwitz [6] 27.0 iprodione Horwitz [6] 24.1 iprovalicarb Horwitz [6] 29.7 phosalone Horwitz [6] Table 5: Number and Percentage of z-scores where z 2 analyte number of scores where total number % z 2 z 2 of scores bifenthrin iprodione iprovalicarb phosalone Page 11 of 38

12 µg/kg Page 12 of 38 z-score Laboratory Number µg/kg 69 µg/kg Figure 1: z-scores for Bifenthrin

13 µg/kg Page 13 of 38 z-score Laboratory Number µg/kg 61 µg/kg Figure 2: z-scores for Iprodione

14 µg/kg Page 14 of 38 z-score Laboratory Number µg/kg 78 µg/kg Figure 3: z-scores for Iprovalicarb

15 µg/kg Page 15 of 38 z-score Laboratory Number µg/kg 46.7 µg/kg Figure 4: z-scores for Phosalone

16 APPENDIX I: Analytical Methods Used by Participants Methods are tabulated according to the information supplied by participants, but some responses may have been combined or edited for clarity. Bifenthrin Accredited Method Used yes no Sample Weight (g) 1 - < < < Extraction Solvent Components acetone acetonitrile cyclohexane dichloromethane ethyl acetate hexane methanol 008 petroleum ether/spirit 018 water Extraction Technique Used cold solvent extraction at atmospheric pressure QuEChERS 009 solvent extraction at increased pressure / PLE 026 SPE Page 16 of 38

17 Extraction ph Adjusted yes no Sample Clean-up Technique carbon based column 012 extraction Florisil column 022 GPC/HPGPC liquid/liquid extraction NH2/aminopropyl column 012 solid phase extraction (SPE) (column/cartridge) solid phase extraction (SPE) (dispersive) none SPE Sorbent Type C Envicarb/GCB 017 Oasis HLB 014 PSA silica 027 none 018 Certified Standards Used yes no MS Confirmation yes no Page 17 of 38

18 Calibrations matrix-matched multi-level single-level solvent standard addition 003 Source of Standards Accu Standard 014 ChemService Dr Ehrenstorfer EPA 014 Fluka 014 FMC agricultura Products 018 Kanto Chemical 008 Merck 014 Sigma/Aldrich Wako 010 Is quoted percentage recovery measured in same analytical batch as test material? yes no If measured, when was the spike added? prior to extraction Level of Spike (µg/kg) < < < Page 18 of 38

19 Level of Spike (µg/kg) (continued) < < < < < Composition of Blank Commodity used for Spiking wine blank provided wine test material provided wine GC Column Type capillary GC Column Packing 65% methyl 35% phenyl polysiloxane % methyl 5% phenyl polysiloxane % Methylsiloxane 003 GC Injection Volume (μl) 1 - < < < Page 19 of 38

20 GC Injection Mode PTV split 018 splitless pulsed splitless 015 GC Detector ECD FPD 022 MS MS-MS NPD HPLC Column Packing C HPLC Guard Column Used yes no Mobile Phase Programme isocratic 023 gradient Mobile Phase Components acetonitrile diethyl ether 003 formic acid methanol water Page 20 of 38

21 HPLC Column Temperature ( C) ambient 003 >ambient - < HPLC Injection Volume (μl) 5 - < < Mobile Phase Flow Rate (ml/min) < HPLC Detector Type MS-MS Iprodione Accredited Method Used yes no Sample Weight (g) < < < Extraction Solvent Components acetic acid 002 acetone acetonitrile Page 21 of 38

22 Extraction Solvent Components (continued) cyclohexane 027 dichloromethane direct injection 006 ethyl acetate hexane petroleum ether/spirit 018 sodium acetate 002 water 008 Extraction Technique Used cold solvent extraction at atmospheric pressure direct injection 006 QuEChERS 009 solvent extraction at increased pressure / PLE 026 SPE Extraction ph Adjusted yes no Sample Clean-up Technique carbon based column 012 extraction Florisil column 022 GPC/HPGPC liquid/liquid extraction NH2/aminopropyl column solid phase extraction (SPE) (column/cartridge) solid phase extraction (SPE) (dispersive) none Page 22 of 38

23 SPE Sorbent Type C Envicarb/GCB 017 Oasis HLB 014 PSA no 018 Certified Standards Used yes no MS Confirmation yes no Calibrations matrix-matched multi-level single-level solvent standard addition 003 Source of Standards Accu Standard 014 Bayer 018 ChemService Dr Ehrenstorfer EPA 014 Fluka 014 Kanto Chemical 008 Sigma/Aldrich Page 23 of 38

24 Source of Standards (continued) Wako 010 Is quoted percentage recovery measured in same analytical batch as test material? yes no If measured, when was the spike added? prior to extraction Level of Spike (µg/kg) < < < < < < < Composition of Blank Commodity used for Spiking wine blank provided wine test material provided wine in-house control 002 GC Column Type capillary Page 24 of 38

25 GC Column Packing 65% methyl 35% phenyl polysiloxane % methyl 5% phenyl polysiloxane % Methylsiloxane 003 DB5-MS 007 GC Injection Volume (μl) 1 - < < < GC Injection Mode PTV pulsed splitless 015 split splitless GC Detector ECD FPD 022 MS MS-MS NPD HPLC Column Packing C endcapped 002 Page 25 of 38

26 HPLC Guard Column Used yes no 008 Mobile Phase Programme isocratic 023 gradient Mobile Phase Components acetonitrile diethyl ether 003 formic acid methanol water HPLC Column Temperature ( C) ambient 003 >ambient - < HPLC Injection Volume (μl) < < < Mobile Phase Flow Rate (ml/min) < HPLC Detector Type MS-MS Page 26 of 38

27 Iprovalicarb Accredited Method Used yes no Sample Weight (g) < < < < Extraction Solvent Components acetone acetonitrile direct injection 006 ethyl acetate 026 methanol water 008 Extraction Technique Used cold solvent extraction at atmospheric pressure direct injection QuEChERS 009 solvent extraction at increased pressure / PLE 026 Extraction ph Adjusted yes no Page 27 of 38

28 Sample Clean-up Technique extraction filter 001 liquid/liquid extraction 025 solid phase extraction (SPE) (column/cartridge) solid phase extraction (SPE) (dispersive) none SPE Sorbent Type C PSA Certified Standards Used yes no 010 MS Confirmation yes no 008 Calibrations matrix-matched multi-level single-level solvent 010 standard addition 003 Source of Standards Accu Standard 001 ChemService 026 Dr Ehrenstorfer Riedel de Haen 015 Page 28 of 38

29 Source of Standards (continued) Sigma/Aldrich 021 Wako Is quoted percentage recovery measured in same analytical batch as test material? yes no If measured, when was the spike added? prior to extraction Level of Spike (µg/kg) < < < < < < Composition of Blank Commodity used for Spiking wine blank provided wine test material provided wine GC Column Type capillary GC Column Packing 95% methyl 5% phenyl polysiloxane % Methylsiloxane 003 Page 29 of 38

30 GC Injection Volume (μl) 1 - < < < GC Injection Mode PTV splitless 026 GC Detector MS MS-MS HPLC Column Packing C endcapped 016 HPLC Guard Column Used yes no Mobile Phase Programme isocratic 023 gradient Mobile Phase Components acetonitrile ammonium acetate 016 diethyl ether 003 formic acid 003 methanol water Page 30 of 38

31 HPLC Column Temperature ( C) ambient >ambient - < HPLC Injection Volume (μl) < < < Mobile Phase Flow Rate (ml/min) < < HPLC Detector Type MS-MS Phosalone Accredited Method Used yes no Page 31 of 38

32 Sample Weight (g) < < < < Extraction Solvent Components acetone acetonitrile cyclohexane dichloromethane ethyl acetate hexane methanol 008 petroleum ether/spirit 018 water Extraction Technique Used cold solvent extraction at atmospheric pressure QuEChERS 009 solvent extraction at increased pressure / PLE 026 SPE 014 Extraction ph Adjusted yes no Sample Clean-up Technique carbon based column 012 extraction Page 32 of 38

33 Sample Clean-up Technique (continued) Florisil column 022 GPC/HPGPC liquid/liquid extraction NH2/aminopropyl column 012 solid phase extraction (SPE) (column/cartridge) solid phase extraction (SPE) (dispersive) none SPE Sorbent Type C Envicarb/GCB 017 Oasis HLB 014 PSA silica 027 no 018 Certified Standards Used yes no MS Confirmation yes no Calibrations matrix-matched multi-level single-level solvent standard addition 003 Page 33 of 38

34 Source of Standards Accu Standard 014 ChemService Dr Ehrenstorfer EPA 014 Fluka 014 Kanto Chemical 008 Merck 014 Sigma/Aldrich Wako 010 Is quoted percentage recovery measured in same analytical batch as test material? yes no If measured, when was the spike added? prior to extraction Level of Spike (µg/kg) < < < < < < < < Page 34 of 38

35 Composition of Blank Commodity used for Spiking wine blank provided wine test material provided wine GC Column Type capillary GC Column Packing 65% methyl 35% phenyl polysiloxane % methyl 5% phenyl polysiloxane % Methylsiloxane 003 DB5-MS 007 GC Injection Volume (μl) 1 - < < < GC Injection Mode PTV pulsed splitless 015 split splitless GC Detector ECD FPD MS Page 35 of 38

36 GC Detector MS-MS NPD HPLC Column Packing C HPLC Guard Column Used yes no 008 Mobile Phase Programme isocratic 023 gradient Mobile Phase Components acetonitrile diethyl ether 003 formic acid methanol water HPLC Column Temperature ( C) ambient 003 >ambient - < HPLC Injection Volume (μl) 5 - < < Page 36 of 38

37 Mobile Phase Flow Rate (ml/min) < HPLC Detector Type MS-MS Page 37 of 38

38 APPENDIX II: FAPAS SecureWeb, Reports and Protocol 1. FAPAS SECUREWEB Access to the secure area of our website is only available to participants in our proficiency tests. Please contact us if you require a UserID and Password. FAPAS SecureWeb allows participants to: Obtain their s for the proficiency tests in which they have participated. View the results they submitted in past and current proficiency tests. Submit their results and methods for current tests. Review future tests they have ordered. Order proficiency tests and quality control materials. Freely download copies of reports, in Acrobat PDF format, of proficiency tests in which they have participated. 2. REPORTS The Acrobat PDF version of this report is available to all participants as a free download from FAPAS SecureWeb. 3. PROTOCOL The Protocols [2, 3] set out how FAPAS is organised. Copies can be downloaded from our website. 4. QUALITY SYSTEMS FAPAS is accredited by UKAS as complying with the requirements of ISO/IEC 17043:2010 The Food and Environment Research Agency is an ISO 9001 certified organisation. 5. CONTACT DETAILS Participants with any comments or concerns about this proficiency test should contact: FAPAS The Food and Environment Research Agency Sand Hutton, York YO41 1LZ UK Tel: +44 (0) Fax: +44 (0) info@fapas.com testmaterials@fapas.com web: Page 38 of 38