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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
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Extraction Methods
Compound optimisation
Retention Time Locking
Limits of Detection
Linearity
Overview
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Agilent 7000A Triple Quadrupole GC/MS
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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
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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
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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
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Optimisation
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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
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Internal Standard TPP
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Quantitation Method
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Calibration
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Qualifier
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Malathion LCL (10ppb)
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Malathion Positive
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Chlorpyriphos LCL (10ppb)
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Chlorpyrifos Positive
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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
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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
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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
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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
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Thank you for your attention
questions?