High Sensitivity and Rugged Pesticide

Residue Analysis in Food Samples by

GC/MS Triple Quadrupole

EPRW June 2010Dr. Finbarr ORegan

Pesticide Control Service,

Department of Agriculture, Fisheries and Food,

Backweston Campus,

Youngs Cross,

Celbridge,

Co. Kildare

Extraction Methods

Compound optimisation

Retention Time Locking

Limits of Detection

Linearity

Overview

Agilent 7000A Triple Quadrupole GC/MS

Fruit and veg. Extraction

Mini-Luke extraction

Acetone , DCM, Petroleum Ether

Sodium Sulphate

GPC Clean-up (also run without GPC)

Samples made up and run in Ethyl Acetate Based on standard multi-residue method published as "Analytical

methods for pesticide residues in foodstuffs" 6th Ed. Ministry of Health

Welfare and Sport - The Netherlands

Fat matrix Extraction

Acetone , Acetonitrile

Celite clean-up

GPC Clean-up

Samples made up and run in Ethyl Acetate

Based on standard multi-residue method published as "Manual of Pesticide Analysis - Vol 1" DFG - Deutsche Forschungsgemeinschaft

Milk and Egg extraction

QuEChERS extraction

Acetonitrile

Sodium Acetate/Acetic Acid Buffer, Magnesium Sulphate and Sodium

Chloride

Samples made up and run in Ethyl Acetate

Based on standard multi-residue method published as J. AOAC Int. 88 615-

629 - Steven J. Lehotay, Katerina Mastrovska & Alam R. Lightfield

Optimisation

200 compounds in two runs

Retention Time Locking Locked to pp-dde

Limits of Detection 10ppb for 178 compounds

20 - 50ppb for remaining 22 compounds

Linearity R2 = 0.999

(captan and captafol can be problematic)

GC-QqQ Method Overview

Internal Standard TPP

Quantitation Method

Calibration

Qualifier

Malathion LCL (10ppb)

Malathion Positive

Chlorpyriphos LCL (10ppb)

Chlorpyrifos Positive

EUPT FV11 Cauliflower Matrix

z-scores

MiniLuke

No GPC EU Median

Mini LukeGC-MSD

No GPCGC-QqQ

azinphos-methyl 0.316 0.409 0.355 -0.44 0.61

Boscalid 0.347 0.495 0.414 -0.65 0.78

buprofezin 0.477 0.681 0.638 -1.01 0.27

cadusofos 0.598 0.639 0.611 -0.09 0.18

carbofuran 0.231 0.218 0.283 -0.73 -0.92

EUPT FV11 Cauliflower Matrix

z-scores

MiniLuke

No GPC EU Median

Mini LukeGC-MSD

No GPCGC-QqQ

deltamethrin 0.144 0.162 0.157 -0.33 0.13

diazinon 1.120 1.550 1.250 -0.42 0.96

isofenphos-methyl 0.411 0.570 0.540 -0.96 0.22

l-cyhalothrin 0.213 0.252 0.266 -0.80 -0.21

metaxyl 0.519 0.460 0.450 0.61 0.09

EUPT FV11 Cauliflower Matrix

z-scores

MiniLuke

No GPC EU Median

Mini LukeGC-MSD

No GPCGC-QqQ

methamidophos 0.416 0.387 0.405 0.11 -0.18

methidathion 0.446 0.528 0.472 -0.22 0.47

monocrotophos 0.516 0.420 0.438 0.71 -0.16

sum parathion-methyl 0.358 0.226 0.320 0.48 -1.18

phosalone 0.285 0.412 0.368 -0.90 0.48

EUPT FV11 Cauliflower Matrix

z-scores

MiniLuke No GPC

EU Median

MiniLuke No GPC

procymidone 0.676 0.811 0.780 -0.53 0.16

triazophos 0.450 0.631 0.538 -0.65 0.69

Thank you for your attention

questions?