Use of CRMs in quality assurance

Transcription

1 The role of organic chemical metrology in food safety for South Africa Maria Fernandes-Whaley Test & Measurement Conference 14 September 2009

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3 Use of CRMs in quality assurance MATRIX HIGH PURITY

4 Food safety FSI category Pesticide residues Veterinary drug residues Mycotoxins Processing contaminants Industrial and environmental chemicals

5 Food safety FSI category Pesticide residues Current NMISA benchmarked measurements Pesticides in solution by GC- MSD CCQM P31c-1 Current NMISA projects Persistent rganic Pollutants project: Chlorinated pesticides, PCBs, dioxins and furans (various matrices) by GCxGC-ID-TFMS. Veterinary drug The extraction of Preparation for the residues chloramphenicol in milk and analysis by LC/MS/MS CCQM P90 Mycotoxins extraction of chloramphenicol in pork muscle tissue and analysis by LC/MS/MS (CCQM P122) Mycotoxin project: chratoxin-a in wine; Mycotoxins in maize (LC/FLD and LC/MS/MS)

6 Food safety FSI category Processing contaminants Industrial and environmental chemicals Current NMISA benchmarked measurements PAHs in mussel tissue (marine) & soil by GC-MSD and GC-TFMS. CCQM P31a-1 Current NMISA projects Melamine project: The extraction of melamine and related analogues in milk by LC/MS/MS Methoxypyrazines in wine by SPME GC-TFMS Persistent rganic Pollutants project: PAHs in soil & sediment by GCxGC-TFMS. Brominated flame retardants in plastic, GC-TFMS.

7 Mycotoxins Toxic secondary metabolites released by fungi growing on various agricultural commodities Turkey X disease 1960 s PTENT TXINS: cyto-, nephro- and neurotoxic, carcinogenic, mutagenic, immunosuppressive, estrogenic effects Produced in the field or in storage Acute Aflatoxicosis (Kenya 2004) Chronic esophageal cancer (Transkei)

8 South African Regulations: Department of Health (human consumption) Aflatoxin (total) Aflatoxin B 1 Aflatoxin M 1 Ergot sclerotia Patulin DEPARTMENT F HEALTH, No. R ctober 2004, FDSTUFFS, CSMETICS AND DISINFECTANTS ACT, 1972 (ACT N. 54 F 1972), REGULATINS GVERNING TLERANCE FR FUNGUS-PRDUCED TXINS IN FDSTUFFS Department of Agriculture (animal feed) Aflatoxin B1 Deoxynivalenol Zearalenone Fumonisin B1 chratoxin-a DEPARTMENT F AGRICULTURE, No. R November 2006, FERTILIZERS, FARM FEEDS, AGRICULTURAL REMEDIES AND STCK REMEDIES ACT, 1947 (ACT N. 36 F 1947), REGULATINS RELATING T FARM FEEDS

9 18.0 Commodities routinely analysed for mycotoxins in SA % labs testing

10 25.0 Mycotoxins routinely analysed in SA 20.0 % labs testing

11 Liquid extraction Immuno-affinity columns Solid Phase Extraction Ion Exchange columns Mycosep columns RSA strips GC-MS GC-FID LC-MS/MS LC-MS HPLC-FLD HPLC-PDA Fluorometry ELISA TLC 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

12 14 Method validation No o. of labs CRMs RMs Spiking Round robin PT None

13 GENERAL PRBLEMS EXPERIENCED Reliable standards Competent technicians required Access to information Finances

14 Main objective assist stakeholders in ensuring their measurements are globally equivalent STAKE HLDERS South African Wine Industry Reference measurement STAKE HLDERS South African Grain Laboratory (SAGL) Agricultural Research Council (ARC) Medical Research Council (MRC) Animal Feed Manufacturers Association (AFMA) Smaller commercial laboratories In-house QC laboratories Reference measurement Proficiency Testing Certified Reference Material

15 H HC CH H H H CH 3 CH NH H HC CH H H 2 N H Cl H CH 3 HC CH H H H CH 3 HC CH H 2 N H H H H CH 3 CH 3 H H 3 C H CH 3 H H H H H H 3 C H 3 C CH 3 CH 3 C H 3 H 3 C C H 3 H 3 C H H H H H H H CH 3 H H

16 Developed analytical method - Maize Mycotoxins Extraction and cleanup: Aflatoxins B1, B2, G1, G2 chratoxin-a Fumonisin B1, B2 T2 toxin HT-2 toxin Deoxynivalenol Zearelenone Various Mycotoxins Measurement Uncertainty Liquid-Liquid extraction Dilute and shoot Analysis: Quantification: UPLC-MS/MS Isotope Dilution

17 Isotope Dilution Mass Spectrometry 13 C/ 12 C sample 13 C/ 12 C calibr SAMPLE CALIBR Measurement Uncertainty

18 (Double) Isotope Dilution Mass Spectrometry IDMS Different chemical structures require different extraction conditions e.g. ratio of ACN:H 2 FBs 50:50 thers -80:20 Requires harsh/extended extraction conditions Isotope exchange interactions 100% extraction Complete equilibration

19 Melamine rganic nitrogen-based compound used in commercial plastics and fertilizer 66% N, used to inflate apparent protein content of food Deaths due to renal failure: 2007: SA pet food made with gluten 60 from China Wheat flour deliberately contaminated with melamine 2008 : milk and milk products in China Melamine masking agent for addition of water to milk SA milk due to animal feed contamination with maize gluten

20 Melamine analogues hydrolysis melamine cyanuric acid Melamine-cyanuric acid-complex

21 South African Regulations: The regulations relating to maximum levels for melamine in foodstuffs have been published in the Government Gazette on 28 January 2009, by the Minister of Health in terms of the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972). The regulations have been published as a draft : Any foodstuff containing Melamine at a level above 1 mg/kg (ppm) for foodstuffs intended for children under 36 months of age and foodstuffs for special dietary uses, 2,5 mg/kg (ppm) for all other foodstuffs, are deemed to be contaminated, impure or adulterated.

22 Main objective - extraction and analysis of melamine in milk assist stakeholders in ensuring their measurements are globally equivalent assist in settling a measurement dispute STAKE HLDERS Department of Health (Pretoria) Department of Health (Cape Town) Smaller commercial laboratories In-house QC laboratories Reference measurement

23 Main objective Develop a method for the extraction and analysis of melamine in milk 1. Investigation of best extraction and cleanup 2. ptimisation of UPLC separation 3. ptimisation of MS/MS ionization and MRM transitions 4. Ruggedness testing 5. Prepare uncertainty budget 6. Investigate PT scheme / NMI bilateral participation

24 Evaluate method Extraction and cleanup: Sonicate with phosphate buffer and acetonitrile Centrifuge SPE Analysis: Aqueous Normal Phase chromatography (HILIC) UPLC-MS/MS Quantification: Melamine in milk, infant formula Measurement Uncertainty Isotope Dilution

25 Use of CRMs in quality assurance MATRIX HIGH PURITY

26 Purity assessment Identify gas chromatography (GC) high performance liquid chromatography (HPLC) Quantify thin layer chromatography (TLC) nuclear magnetic resonance (NMR) titrimetry differential scanning calorimetry (DSC) mass spectrometry (MS) thermal gravimetric analysis (TGA) Karl Fischer titrimetry infra-red (IR) ultraviolet (UV) spectroscopy

27 Purity assessment Identify Quantify Direct Assay Impurity Subtraction Gravimetry Titrimetry Quantitative NMR

28 Purity assessment Identify Quantify Impurity Subtraction Primary Method Secondary Method

29 Purity assessment Identify DSC - % purity (check) major component confirmation LC-UV, LC-(ESI/ APCI)-MS/MS GC-FID, GC-TFMS H 1 -NMR C 13 NMR IR TGA

30 Purity assessment Impurity Subtraction Primary Method Secondary Method Karl Fischer Coulometric & Volumetric Titration TGA GC-FID, GC-TFMS LC-UV, LC-(ESI/APCI)-MS/MS Quantification: RRF & Peak area % External calibration

31 CCQM AWG participation Comparison Substance Date P20.e Theophylline Jan 2007 K55.a 17β-Estradiol Mar 2009 K55.b Aldrin Feb 2010 K55.c xytetracycline Feb 2011 K55.d Fumonisin / Patulin Feb 2012

32 Conclusion NMISA organic laboratory may assist with traceable measurements in food safety analytical laboratories through the provision of: Reference measurements IDMS Certified reference materials high purity matrix (long-term) Benchmark capability through international comparisons

33 Acknowledgements Colleagues in the NMISA organic laboratory Des Prevoo Jayne de Vos Ria Visser Tshepiso Mphamo Marcellé Archer Participants in the National Mycotoxin Survey