Polar Pesticides Method Update

Transcription

1 Polar Pesticides Method Update Philip Taylor SCIEX 2018

2 Introduction FMOC derivatisation normal but time and labour intensive QuPPe extraction and more sensitive instrumentation have enabled an underivatised approach for food testing Public awareness and concerns about safety have increased pressure on regulators and testing organisations Limits changed over the years from 500 µg/kg to 10 µg/kg Environmental regulations are more challenging many labs demand lower than the recommended level of 0.1ng/L Sensationalist media coverage has played an important role:

3 Introduction Chromatography remains difficult & matrix interferences challenging Several approaches to a solution have been tried Trinity method at US-FDA 3 x possible separations in EURL protocol (Based on IC or Hypercarb) 2D IC application from Thermo HILIC at Waters & Sielc Robustness and ultimate sensitivity are big challenges e.g. EURL recommend conditioning Hypercarb with 20x spinach extracts prior to analysis. Stability limited (<100 samples), reconditioning often not possible New Column After 30 injections of Spinach After samples

4 Work at NofaLab Food safety contract lab in Rotterdam harbour Specialise in nuts, oils, fats and seeds Public interest in glyphosate particularly high in NL Commercial need to stay ahead and meet increasing demand Unhappy with robustness of current methods Performance in complex matrices using QuPPe extracts Wim Broer developed LC-MS/MS method using ion suppressor Broad peaks, long runtime NofaLab needed higher level of confidence Looked into newest available triple quads

5 Work at NofaLab Cleanup was required to maintain a clean instrument and stable performance Modification of QuPPe recommendation for foods of animal origin applied to all samples Source cleanliness maintained >100 samples Original work with suppressor Better sensitivity Poor peak shapes and long retention WO suppressor With suppressor

6 The NofaLab Method Found QTRAP significantly more sensitive and flexible Allowed for modification of mobile phase and removal of suppressor Sharper, more intense peaks, shorter run time IC column, LCMS amenable buffers at relatively low concentration Standard UHPLC inlet (Shimadzu Nexera) Sensitivity better than required for food regulations <10ppb (glyphosate) for QuPPe extracts for all but the most complex matrices Robust solution ~1000 samples on single column without need to recondition Applicable to multiple analytes Glyphosate, AMPA, ethephon, gluphosinate, N-ac gluphosinate, 3-MPPA, chlorate, perchlorate, fosetyl, phosphonic acid

7 Final NofaLab Method for QuPPe Extracts of Food Samples

8 Internal Validation in Food Matrices Multiple analyte/matrix combinations Product group usage Products used for validation High water content, High acid content and high water content en High sugar and low water content Babyfood Dried fruit and vegetables High oil content (seeds) Babyfood Rape and sunflower seeds and soybeans High oil content (edible oil) Babyfood Sunfloweroil and rapeseed oil High starch and/or protein content and low water and fat content Difficult or unique commodities (spices) Babyfood Grain Chilipowderr and nutmeg Meat (muscle) and seafood Bbyfood Dried beef Milk and milkproducts Babyfood Milkpowder Eggs Babyfood Eggpowder Fat from food of animal origin Fatty acids Fishoil Mixed fatty acids

9 Internal validation in food matrices Robustness over 1000 samples (guard changed every 250) Parameter Sample Type Retention time Width at 50% Tailing Factor Average RSDR Average RSDR Average RSDR 3-MPPA is Standard % % % Unknown % % % AMPA is Standard % % % Unknown % % % Chlorate is Standard % % % Unknown % % % Ethephon is Standard % % % Unknown % % % Fosetyl is Standard % % % Unknown % % % Glufosinate is Standard % % % Unknown % % % Glyphosate is Standard % % % Unknown % % % Phosphonic acid is Standard % % %

10 Internal validation in food matrices Excellent reproducibility and sensitivity for regulations in all matrices Product Glufosinate Fosetyl Glyphosate Chlorate Ethephon LOD MRL RSDr at MRL LOD MRL RSDr at MRL LOD MRL RSDr at MRL LOD MRL RSDr at MRL LOD MRL RSDr at MRL Fruit and Vegetables % % % % % Seeds % % % % % Vegetable oil, Fat and Fatty Acids % % % % % Grain % % % % % Herbs and spices % % % % % Meat and Seafood % % % % % Animal Oil, Fat and Fatty Acids % % % % % Eggs and Eggs products % % % % % Milk and Milk products % % % % % Fatty acids % % % % %

11 Method development for water samples Higher injection volume Higher background! Peak shape and Rt stability suffer Early eluting interferences from organic acids lead to high suppression Earlier studies show complete loss of signal between Milli-Q and tap water Demanding LoQ of 20ppt Co-eluters which are not important for food samples become troublesome n.b. Some prior success demonstrated with IonPac but need to recondition with Sodium Hydroxide (NaOH) after every X sample injections

12 Chromatography in standard Glufosinate AMPA Glyphosate Fosetyl

13 Modified Method for Environmental Waters Same setup as for food samples except 500μl loop Swift change between food & environmental samples And between IC and RPLC compound suites Different ph gradient Optimisation of peak shape Better separation to counter matrix effects High sensitivity LoQs ppt Robustness to be tested further... Linearity, CV and Rt stability are good Importantly, good retention of analytes means matrix interferences are minimised.

14 Glyphosate 15.6ppt to 1000ppt Good sensitivity, linear response and ion ratios <20% tolerance

15 Glyphosate in surface water samples Confirmed by standard addition & previous FMOC results

16 AMPA 20 ppt to 450 ppt

17 AMPA Reproducibility (8 injection)

18 AMPA in River Water samples Previously tested by FMOC Negative Negative 110ppt 65ppt 13ppb

19 Conclusion IC on UHPLC system with QTRAP Flexible and appropriate for high throughput routine lab Allows switching between polar & normal pesticide suites without changing inlet Robust and sensitive Validated >1000 food samples with single column Meets all MRLs for food commodities and water regulations Ion ratios within regulatory guidelines for all but the most complex samples Available to demo now Method free-of-charge to TQ and QTRAP users Under NDA

20 Thanks Wim Broer, NofaLab Ugo Chiuminato & Jianru Stahl-Zeng, Sciex Future Work Validation on different systems in D, UK and NL Robustness testing in more real samples

21 Sciex Environmental Testing Hub All application notes, product information, webinars and training available free of charge:

22 Thank You

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