ESAC 2006 Copenhagen. New Developments in LC/MS & GC/MS Screening Methods for Food Safety and Environmental Monitoring.

Transcription

1 ESAC 2006 Copenhagen New Developments in LC/MS & GC/MS Screening Methods for Food Safety and Environmental Monitoring Dr Sandra Rontree

2 Overview Trend in analytical method development Method Requirements New technologies UPLC/LCT Premier Pesticide screening in drinking water and vegetables Veterinary drug residues in milk Illegal dyes in ground spices GCT Premier Pesticides in fruit and vegetables Priority pollutants in environmental samples Conclusions

3 Food Safety analysis Trend in analytical method development Sample preparation Compoundspecific Generic Generic Generic Analytical method Compoundspecific Multiple residues Generic Generic Determination of Known Known Known Unknown Analysis Targetcompound Targeted analysis Targeted analysis Screening analysis

4 Today s Analytical Chemist The Daily Challenge: Analysis of Complex Mixtures The KNOWN (or suspected residue) Routine monitoring program SIM or MRM normally used Single quad, Tandem quad, Sector Targeted analysis The UNKNOWN Environmental contamination Full spectrum will have to be used Time of Flight (TOF) Screening analysis?

5 UPLC/LCT Premier GCT Premier New Technologies

6 Screening Applications GCT/LCT Premier Screening methods Large numbers of target compounds, quick methods Positive samples to tandem quadrupole for quan and confirmation Advantages of oa-tof Full spectrum data at high sensitivity Detection of unexpected compounds in addition to targets Would not be seen using triple quad MRM Large number of compounds in one run Not necessary to set up large no. of MRM transitions Exact mass measurement To confirm presence of knowns or identify unknowns

7 The Use of ACQUITY UPLC and Time of Flight Mass Spectrometry for the Analysis of Contaminants in Food UPLC/LCT Premier TargetLynx ChromaLynx

8 High Resolution Chromatography: Influence of Particle Size AU AU HPLC 5 µm Peaks = µm Peaks = 168 UPLC TM Minutes

9 ACQUITY UPLC Challenges Smaller particles produce higher column backpressures Whole system operates at up to 15,000 psi Including the autosampler Ethyl-bridged hybrid column chemistry Mechanically strong Wide ph range UPLC TM An Introduction and Review, M. E. Swartz, J. Liq. Chromatogr. Rel. Technol., 2005, 28(7-8), pp C 8, C 18, Shield C 18 (embedded polar carbamate group) and Phenyl stationary phases

10 LCT Premier key features Exact mass measurement <3ppm RMS mass accuracy High sensitivity Full spectra always acquired Enhanced Resolution V or W TOF analyser geometries for >5,000 or >10,000 FWHM resolution Enhanced Dynamic Range Up to 4 orders of dynamic range for wider analytical applicability Positive/Negative Ion Mode Switching 0.2 secs for exact mass

11 Resolution Comparison 100 Quadrupole = Unit Resolution LCT Premier V Mode = 6000 FWHM LCT Premier W Mode = 11,000 FWHM % m/z

12 Pesticide Library Screening using UPLC/Tof MS US EPA currently has a list of target deleterious organic compounds Homeland security Screening drinking water during contamination emergencies Various EU food safety and environmental laboratories are investigating UPLC/ToF for Pharmaceuticals in environmental samples Veterinary drug residues in animal tissue Illegal dyes in foodstuffs

13 Screening Requirements Extract, detect, locate and identify all components Non-selective sample preparation for a wide range of compound groups with different polarities GC or UPLC chromatographic separation to minimise matrix interference whilst maintaining resolution of critical pairs High sensitivity Full mass spectrum Automated peak detection and deconvolution of all components in the sample Automated production of background subtracted spectra for each component Automated library search and identification Exact mass may help identification Estimate the concentrations of all the components in the sample

14 Exact Mass Example Carbaryl C 12 H 12 NO 2 Monoisotopic mass m/z Thiabendazole C 10 H 8 N 3 S Monoisotopic mass m/z Difference is 212 ppm

15 Exact Mass Chromatograms

16 How does ppm deviation effect list of possible elemental formulae? 2 ppm limit 6 ppm limit

17 How do element parameters effect list of possible elemental formulae? 6 ppm limit. C, H, N and O selected 6 ppm limit. C, H, N, O, F, P, S, Cl and Br selected

18 How does m/z effect list of possible elemental formulae? 6 ppm limit. C, H, N and O selected, m/z ppm limit. C, H, N and O selected, m/z 789

19 Ciprofloxacin C 17 H 18 N 3 O 3 F i-fit

20 LC/Tof MS Analysis of Pesticide Residues in Drinking Water 95 compounds analysed - 6 in negative ion mode Spiked into Manchester drinking water 13.5 min overall cycle time Simultaneous positive and negative ionisation

21 Quantitative Performance Calibration curve for Ioxynil Negative ionisation with polarity switching

22 ChromaLynx Software Detect and locate all components in the sample Automated deconvolution and chromatographic peak detection of all components Clean, individual mass spectrum for each component in the sample Automatic production of background subtracted spectra Exact mass measurement is retained from TOF Identify components in the sample Automated library searching

23 ChromaLynx Browser

24 Case study Veterinary drug residues Peter Fuerst, CVUA, Munster: EU food reference lab National Residue Control Plans EU Commission Need to test 0.5% of all slaughtered pigs, 2% of all calves 3,500 samples p.a. at CVUA, 25,000 in total >99% of samples are negative Quick screening method required for veterinary drugs ACQUITY UPLC-LCT Premier combination Confirmation of positives by tandem quad MS/MS

25 Sudan IV Picked out from 678 Components in Chilli Powder

26 Dimethyl Yellow and Rhodamine B Co-eluting components

27 Veterinary Drugs: Fenbendazole at 10 ppb in Milk

28 UPLC/LCT Premier GCT Premier New Technologies

29 Application of Elevated Resolution GC-TOF-MS for the Multiresidue Analysis of Pesticides

30 Overview Pesticide Residues in Food Commodities Introduction to GCT Premier Targeted Screening of Pesticide Residues in Food Application of Method to Matrix-Matched Standards Cucumber, Sweet Pepper, Grapefruit, Flour Application of Method to Real Samples TargetLynx Application Manager Untargeted Screening of Pesticide Residues in Food Screening Requirements Application of Method Cucumber, Sweet Pepper, Grapefruit ChromaLynx Application Manager

31 Past Situation Did not always exist and were not totally harmonised Range from not detectable to approximately 50mg/kg Not detectable differed from country to country EU Legislation Regulation (EC) 369/2005 of 23 th February 2005 Harmonised for all pesticide/product combinations Range from not detectable to approximately 50mg/kg Not detectable defaults to 0.01 mg/kg if no other level is assigned Recommendation 2006/26/EC of 18 th January 2006 Coordinated monitoring programme to ensure compliance with maximum levels of pesticide residues in or on cereals and certain other products of plant origin General target LOD = 0.01 mg/kg Some exceptions, e.g. baby food, medicinal plants

32 GCT Premier Orthogonal Acceleration TOF Rapid full spectral sampling and acquisition rates Non skewed spectra Narrow chromatographic peaks Accurate chromatographic peak profiling enabling deconvolution Non scanning instrument with a high duty cycle High full scan sensitivity Predictable scan law Routine exact mass calibration with a single lock mass Elevated Resolution Enhanced selectivity

33 Plug in EI/CI ion volumes for rapid change over Resolution Greater than 7000 (Full width half maximum) Exact mass Less than 5 ppm RMS Dynamic range 4 orders linear dynamic range Spectral acquisition rate 20 spectra per second GCT Premier

34 Pesticide Residues Azoxystrobin Biphenyl Buprofezin Chlorpyrifos Cyprodinil Dichloran Dichlorobenzophenone Diethofencarb Diphenylamine Etrimfos Fenarimol Fipronil Fludioxonil Iprodion Kresoxim-methyl Malathion Mepanipyrim Metalaxyl Myclobutanil OPP PCB 138 (I.S.) Pirimicarb Pirimiphos-methyl Procymidon Profenofos Pyrimethanil Pyriproxyfen Pyridaben Quinoxyfen Quizalofop-ethyl Tebufenpyrad TPP (I.S.) Vinclozolin

35 Total Ion Chromatogram (TIC) Biphenyl Azoxystrobin

36 Targeted Screening TOF Compound list is known Extracted exact mass chromatograms, 0.02 or 0.05 Da window Full spectrum technique Any ion can be chosen for quantification Number of residues/ions can be increased without loss in sensitivity Screening is based on one or more exact mass chromatograms TargetLynx application manager Highlight samples that have concentrations greater than the reporting level do not pass quality control criteria

37 Selectivity of Exact Mass Chromatograms Fludioxonil, 0.01 mg/kg in Cucumber, m/z = Da 0.02 Da

38 Selectivity of Exact Mass Chromatograms Fludioxonil, 0.01 mg/kg in Grapefruit, m/z = Da 0.02 Da

39 Linearity Compound name: Pyrimethanil Correlation coefficient: r = , r^2 = Calibration curve: * x Response type: Internal Std ( Ref 1 ), Area * ( IS Conc. / IS Area ) Curve type: Linear, Origin: Exclude, Weighting: 1/x, Axis trans: None Response Concentration Range pg/µl equivalent to mg/kg Pyrimethanil in Flour r 2 = Conc

40 Application to Real Samples Orange, Cherry Tomato, Grapes, Kiwi, Strawberry Cucumber standards were used for calibration TargetLynx application manager used for automatic quantification and confirmation 2 exact mass chromatograms per residue were acquired with ± 30% as the tolerance for the ion ratios Reporting Level = 0.005mg/kg Maximum Residue Limit = 0.010mg/kg

41 Kiwi Procymidon 0.057mg/kg

42 Untargeted Screening TOF Compound list is unknown Full spectrum technique with no spectral skew Fast acquisition speed enables deconvolution, spectra / s Exact mass may help identification, < 5 ppm RMS High resolution allowing enhanced selectivity, > 7000 FWHM ChromaLynx application manager Automatic peak detection and deconvolution Automatic production of clean component spectra Automatic identification via library searching Exact mass confirmation

43 Deconvolution 5 Components?

44 Deconvolution with ChromaLynx ChromaLynx found 7 Components!

45 Extracted Mass Chromatograms 3 Components Dichlorvos 2,6-dichloroaniline 1-chloro-3-nitrobenzene

46 Cucumber ChromaLynx ChromaLynx found ~ 550 Components 33 compounds were 0.05 mg/kg

47 Library searching can be confirmed by exact mass in ChromaLynx Cucumber Exact Mass Confirmation

48 Conclusions TOF technology with full MS spectra enables targeted analysis, detects unexpected compounds and identifies unknown contaminants Targeted and untargeted screening of pesticide residues, veterinary drugs and illegal dyes using the UPLC/LCT Premier with TargetLynx and ChromaLynx has been presented A method has been presented for the targeted screening of pesticide residues in food commodities using the GCT Premier with TargetLynx The residues can be screened to concentration levels of 0.01 mg/kg or less in cucumber, sweet pepper, grapefruit and wheat flour with the use of exact mass chromatograms The method can also be extended to larger numbers of residues without loss in sensitivity due to the full spectrum approach provided by TOF instruments The described method was tested on real samples where incurred pesticide residues were confirmed This single injection can also be used to screen for untargeted residues in the same extract with ChromaLynx ChromaLynx enables automatic detection, deconvolution, library searching and exact mass confirmation

49 Acknowledgements Waters Corporation, Manchester, UK Peter Hancock, Gordon Kearney, Dan McMillan CVUA, Stuttgart, Germany Carmen Wauschkuhn Diane Fuegel Michelangelo Anastassiades