🍎 Pesticide Residues in Foods of Plant Origin — QuEChERS Method

Food Chemistry PN-EN 15662

Overview

STATUS (as of 02.11.2026). PN-EN 15662:2018-06 — English and Polish versions (the Polish one published on 30.01.2023), implements EN 15662:2018 [IDT]; replaced PN-EN 15662:2008; the PKN catalogue card has no withdrawal note (read on 02.11.2026). EN 15662:2018 (approved by CEN on 27.12.2017, published in May 2018) replaced EN 15662:2008. Changes according to the foreword: a more precise distinction between procedural options (Tables 1–5) and a simple way of recording them in the test report, recommended options for specific commodities (Table 6), a longer extraction time, UPLC-MS/MS and GC-MS/MS detection parameters, new quantification approaches with simplified calculation of residues, a reference to validation data (CEN/TR 17063) and a list of abbreviations (Annex C). The description is based on the preview of EN 15662:2018 (iTeh: foreword, clauses 1–4, overview of the modules with Tables 1–5 and the beginning of Table 6) and on the description of the method by its authors (CVUA Stuttgart).

ORIGIN. The QuEChERS method (Quick, Easy, Cheap, Effective, Rugged and Safe) was developed by M. Anastassiades in 2001–2002 in the team of S. Lehotay (USDA, Wyndmoor); it was presented in 2002 and published in detail in 2003 (J. AOAC Int. 86: 412–431). The version with acetate buffer became AOAC Method 2007.01, and the version with citrate buffer, developed further at CVUA Stuttgart, became the standard EN 15662.

SCOPE (clause 1). Analysis of pesticide residues in foods of plant origin, such as fruit (including dried fruit), vegetables (including dried vegetables), cereals and many of their processed products, by GC, GC-MS(/MS) and/or LC-MS(/MS). The method has been tested in interlaboratory studies for a large number of commodity–pesticide combinations; the precision data are compiled in CEN/TR 17063 and the calibration guidance in CEN/TS 17061.

PRINCIPLE (clause 3). The homogeneous sample is extracted with acetonitrile; for samples containing less than 80 % water, water is added before the extraction so that the total amount is about 10 g. After the addition of magnesium sulfate, sodium chloride and buffering citrate salts, the mixture is shaken intensively and centrifuged. An aliquot of the organic phase is cleaned up by dispersive solid-phase extraction (D-SPE) with bulk sorbents and magnesium sulfate, which removes residual water; after clean-up with an amino sorbent (PSA) and, if necessary, graphitized carbon black (GCB) or octadecylsilane (ODS), the extracts are acidified with a small amount of formic acid to improve the stability of base-sensitive pesticides. The final extract is suitable directly for GC and LC analysis; GC detectors: mass spectrometers (MS, MS/MS) or others, e.g. FPD and ECD; for LC, tandem mass spectrometry or high-resolution mass spectrometry is particularly suitable. An internal standard added to the test portion before the first extraction may be used but is not mandatory.

SAMPLE (clause 4). Preparation and storage shall not significantly change the residues, and the sample shall be homogeneous enough for the test portions not to differ. Only the part of the laboratory sample to which the maximum residue level applies is taken for the test sample; it is reduced in a representative way (e.g. quartering); stones are removed from stone fruit, but the result is calculated on the mass including the stones. Comminution in the frozen state reduces losses of labile pesticides; it is made easier by cutting the sample beforehand (e.g. 3 cm × 3 cm) and freezing it (e.g. at −18 °C overnight), and cryogenic milling (dry ice or liquid nitrogen) keeps the temperature below 0 °C. Test portions are analysed immediately, otherwise frozen.

MODULES (clause 5, Tables 1–5). Extraction E1–E9, for example: E1 — 10 g of sample without added water (products containing at least 80 % water: fruit, vegetables, juices); E2 — 10 g with 10 ml of acetonitrile after addition of 0.6 ml or 0.2 ml of sodium hydroxide solution (very acidic products, e.g. lemons, raspberries); E3 — 10 g with 2.5 ml or 4.5 ml of water (from 40 % to 80 % water); E4 — homogenate with water, 13.5 g (from 15 % to 40 % water, dried fruit); E5 — 5 g with 10 ml of water (less than 15 % water: cereal grains and cereal products, honey); E6 — 5 g with 6 ml of water (fatty products or products with a high matrix load: garlic, avocado); E7 — 2 g with 10 ml of water (spices, coffee, tea, lentils, freeze-dried products); E8–E9 — with hydrolysis of esters and conjugates of acidic pesticides. Clean-up C0–C5: C0 without clean-up (acidic and base-sensitive pesticides, extracts with a low matrix load), C1 freezing-out of fat, C2 D-SPE with PSA (standard procedure), C3 with a larger amount of PSA, C4 PSA with ODS (removal of fat), C5 PSA with GCB (strongly coloured extracts). Stabilization: S1 with formic acid (most analytes), S0 without stabilization (analytes unstable in acidic media). Detection D1–D6: LC-MS/MS, LC-HR-MS, GC-MS/MS, GC-MS, GC-FPD (organophosphorus and sulfur-containing compounds), GC-ECD (organochlorine compounds). Quantification Q1–Q7 according to CEN/TS 17061 — standards in solvent or in matrix, procedural internal standard, standard addition, calibration of the whole procedure.

AMOUNTS OF REAGENTS (description of the method by CVUA Stuttgart). A mixture of 4 g ± 0.2 g of anhydrous magnesium sulfate, 1 g ± 0.05 g of sodium chloride, 1 g ± 0.05 g of trisodium citrate dihydrate and 0.5 g ± 0.03 g of disodium hydrogen citrate sesquihydrate is added to 10 g of sample and 10 ml of acetonitrile; the tube is shaken by hand for 1 min and centrifuged. The citrate salts give a pH of 5 to 5.5 for most samples. For D-SPE, 25 mg of PSA and 150 mg of magnesium sulfate are used per 1 ml of extract (shaking for 30 s); for extracts rich in carotenoids or chlorophyll GCB is added — for example 2.5 mg or 7.5 mg per 1 ml — and fat is removed with C18 sorbent (25 mg per 1 ml) or by freezing out. Table 6 of the standard gives the same figures for individual commodities — PSA 25, GCB 2.5 or 7.5, C18 25, and for more difficult matrices PSA 50 or 75. The original 2003 version — 10 g of sample, 10 ml of acetonitrile, 4 g of magnesium sulfate and 1 g of sodium chloride, D-SPE with 150 mg of magnesium sulfate and 25 mg of PSA per 1 ml of extract — had no buffer; PSA removes, among other things, organic acids, some polar pigments and sugars from the extract.

WHAT WE DO NOT GIVE HERE. Detailed descriptions of the modules (Annex A), chromatography and mass spectrometry parameters, the evaluation of results, confirmatory tests and precision data (clauses 6–8) — these parts of the standard are not in the preview. Nor do we give the number of pesticides determined, limits of quantification or recovery criteria: the criteria for quality control and validation in pesticide residue analysis in the EU are contained in the guidance document SANTE/11312/2021 (currently version v2026).

Method principle

The homogeneous sample (usually 10 g; dry samples in a smaller test portion with water added to about 10 g of water) is extracted with acetonitrile. After the addition of magnesium sulfate, sodium chloride and buffering citrate salts (pH about 5–5.5), the mixture is shaken and centrifuged — the acetonitrile layer separates from the aqueous one.

An aliquot of the extract is cleaned up by dispersive SPE: magnesium sulfate binds residual water, PSA removes, among other things, organic acids and sugars, and if necessary GCB removes pigments and ODS removes fat. The extract is stabilized with formic acid and analysed by GC (e.g. GC-MS/MS) and LC (e.g. LC-MS/MS) techniques.

Applications

• Fruit and vegetables, including dried ones, and juices — modules E1–E4 (clause 1, Table 1)
• Cereal grains and cereal products, honey — module E5; spices, coffee, tea, lentils, freeze-dried products — module E7 (Table 1)
• Checking compliance with the maximum residue levels for pesticides set in Regulation (EC) No 396/2005 — the test sample is prepared from the part of the product to which that level applies (4.3)
• Acidic pesticides — determination in the raw extract without PSA (module C0) or after hydrolysis of esters and conjugates (modules E8–E9)

Key parameters

Standard

Standard number

PN-EN 15662:2018-06

Title (PL)

Żywność pochodzenia roślinnego — Multimetoda do oznaczania pozostałości pestycydów z zastosowaniem analizy opartej na GC i LC po ekstrakcji/podziale acetonitrylem i oczyszczaniu metodą dyspersyjnej SPE — Metoda modułowa QuEChERS

Title (EN)

Foods of plant origin — Multimethod for the determination of pesticide residues using GC- and LC-based analysis following acetonitrile extraction/partitioning and clean-up by dispersive SPE — Modular QuEChERS-method

Step-by-step procedure

1. Preparation of the sample

   Part of the product covered by the maximum residue level, representative reduction, removal of stones (result on the mass including stones); preferably cryogenic milling (4.3–4.4).

2. Extraction

   Test portion according to module E (e.g. 10 g of moist sample, 5 g of grain with 10 ml of water, 2 g of spices with 10 ml of water) and 10 ml of acetonitrile; shaking (Table 1; CVUA description).

3. Phase separation

   Addition of magnesium sulfate, sodium chloride and citrate salts, immediate intensive shaking, centrifugation (clause 3; CVUA description).

4. D-SPE clean-up

   Aliquot of the extract with PSA and magnesium sulfate (C2), if necessary with GCB (C5) or ODS (C4) or after freezing-out of fat (C1); for acidic pesticides — extract without clean-up (C0) (Table 2).

5. Stabilization

   Acidification of the extract with a small amount of formic acid (S1), except for analytes unstable in acidic media (S0) (Table 3).

6. Determination and quantification

   GC and LC with the detectors in Table 4; calibration and calculation according to CEN/TS 17061 (options Q1–Q7, Table 5).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• The standard does not address all safety problems associated with its use — safety measures and compliance with regulations are the responsibility of the user (warning in the standard)
• Acetonitrile is flammable and harmful, formic acid is corrosive — follow the safety data sheets; when milling with dry ice, allow the carbon dioxide to sublime before weighing (4.4)

Frequently asked questions