High Sensitivity and Rugged Pesticide Residue …...High Sensitivity and Rugged Pesticide Residue Analysis in Food Samples by GC/MS Triple Quadrupole EPRW June 2010 Dr. Finbarr O’ReganPesticide

High Sensitivity and Rugged Pesticide

Residue Analysis in Food Samples by

GC/MS Triple Quadrupole

EPRW June 2010Dr. Finbarr O’Regan

Pesticide Control Service,

Department of Agriculture, Fisheries and Food,

Backweston Campus,

Young’s 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?