To compare a result with market limits, use the GB residue guide or NI export guide.
Fera offers multi-residue screens and separate tests for glyphosate, inorganic bromide, and chlormequat with mepiquat.
Pesticide residue analysis in fruits and vegetables and in food products: follow the analytical chain
This is how a laboratory carries out the chemical analysis of pesticides and the detection of pesticides in food, including fruit and vegetables. The analytical workflow runs from sample reception through chopping, freezing and homogenisation to extraction, cleanup, instrumental analysis and reporting.
Understand the role of QuEChERS
QuEChERS preparation combines salt-assisted liquid extraction with dispersive solid-phase cleanup. A tomato method using this preparation measures the extract by triple-quadrupole gas chromatography/mass spectrometry. Sample preparation removes interfering material before chromatographic separation and detection.
Why the food matrix matters
Sulfur-containing compounds in leek and garlic complicate pesticide quantification. Matrix-matched calibration addresses interference from the surrounding food material.
Distinguish GC-MS/MS and LC-MS/MS
Gas- and liquid-chromatography tandem mass spectrometry cover complementary pesticide groups. Some substances require dedicated single-residue methods.
Targeted quantification and screening use different acquisition and interpretation approaches.
Pesticide residues examples: GC-MS/MS analysis of leek and garlic
A GC-MS/MS method for 213 pesticide residues in leek and garlic combines QuEChERS extraction with matrix-matched standards. The method identifier is 5991-6381EN, October 2015.
Distinguish screening from a quantified result
A black-pepper screening method uses Revident LC/Q-TOF, comparing fast polarity switching with separate polarity acquisition. Identification combines accurate mass, retention time and configured screening criteria. The method appears in Agilent publication 5994-8751EN, October 2025.
Recovery, calibration and method validation
For the tomato method, recovery experiments test extraction and measurement of added residues. Calibration and chromatograms show how the configured method responds.
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Interpret the report's reporting threshold
A limit of quantification describes the concentration the method can quantify to its stated performance.
Agree sampling and traceability before dispatch
Keep the commodity, origin and consignment reference attached to the sample throughout transport. HSE's surveillance programme excludes samples compromised in transit.
Ask what supports the analytical method
Method evidence includes the analytical principle, reagents, apparatus, preparation, fortification, calibration, representative chromatograms, calculations, validation and extraction efficiency.
Interpreting recovery and calibration evidence
A fortified sample contains a known addition of pesticide. Recovery compares the amount measured with that addition, while replicate measurements show variation. Calibration relates the instrument response to known concentrations. Matrix-matched standards include the food background so interference is assessed in the material being tested.
In the leek-and-garlic experiment, most recovery results fell between 80% and 120%, with relative standard deviations below 20%. Limits of quantification ranged from 2 to 10 µg/kg. These figures describe the specified experimental preparation, acquisition settings and analyte panel.
A chromatogram concerns the measured signal, while extraction efficiency concerns recovering material from the matrix.
In the leek-and-garlic setup, splitless injection introduces the extract into the gas chromatograph. An autosampler supplies the injection, and a timed oven programme separates compounds on the analytical column. The triple-quadrupole detector monitors selected mass transitions.
Coelution of food-background compounds can suppress or enhance the pesticide signal. In GC-MS/MS, matrix components can block active sites in the inlet or column.
What the instrument specification describes
QuEChERS abbreviates quick, easy, cheap, effective, rugged and safe. The leek-and-garlic method uses solvent extraction and dispersive cleanup before gas chromatography. A helium carrier transports the injected extract through the column, and electron ionisation precedes triple-quadrupole mass analysis.
Column separation, mass transitions and retention times help distinguish pesticide targets from food-background compounds.
Next step
See the GB MRL guide and the NI and EU residue guide.