🍎 Determination of low-level residues of dithiocarbamate fungicides and thiuram disulfide in non-fatty foods as a sum expressed as carbon disulfide — the test portion (up to 200 g, baby food 400 g) is boiled for 30 min with tin(II) chloride solution in hydrochloric acid, the released CS2, purified in traps with sodium hydroxide and sulfuric acid, is absorbed in methanolic potassium hydroxide solution as potassium xanthogenate, and its absorption is measured at 302 nm with correction at 272 and 332 nm; calibration curve 1–40 µg CS2, PN-EN 12396-3

Food chemistry PN-EN 12396-3

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of SIST EN 12396-3:2001 (English text of EN 12396-3:2000, scan): from the title page through the contents, foreword and Clauses 1–7 to 8.4.3 (spectrometric measurement and equation (1) for absorption correction) on page 7. Outside the sample remain the expression of results (9), confirmatory tests (10), precision (11), test report (12), Annex A (precision data) and the bibliography.

ACCORDING TO THE TEXT OF EN 12396-3:2000. The standard was prepared by CEN/TC 275 “Food analysis — Horizontal methods”, whose secretariat is held by DIN; CEN approved it on 08.04.2000, and national implementation was due by November 2000 at the latest. EN 12396 has three parts: 1 — spectrometric method, 2 — gas chromatographic method, 3 — UV spectrometric xanthogenate method. Scope (1): a UV spectrometric method for the determination of low-level residues of dithiocarbamate and thiuram disulfide fungicides as xanthogenate; these compounds release carbon disulfide under specified conditions (e.g. mancozeb, maneb, propineb, thiram, zineb); the method is applicable especially to those foodstuffs of plant origin for which low maximum residue levels have been set; only the whole group can be quantified, individual compounds are not identified; maximum residue levels (MRLs) are generally expressed in terms of carbon disulfide. References (2): ISO 1750 (common names of pesticides), EN 12393-1:1998, EN 12396-1:1998, EN 12396-2:1998. Principle (3): the sample is heated with hydrochloric acid and tin(II) chloride to release carbon disulfide from any dithiocarbamates and/or thiuram disulfides present; CS2 is separated and purified by distillation and collected in methanolic potassium hydroxide solution, where it forms potassium xanthogenate; the absorption of the product is measured at 302 nm with base line correction at 272 and 332 nm, and the mass fraction of residues is expressed in milligrams of carbon disulfide per kilogram of food. Reagents (4): reagents of recognized analytical grade, preferably for pesticide residue analysis, distilled or demineralized water; contamination of water, solvents and inorganic salts by plastics and rubber is to be avoided — only glass containers are used for storing and handling water and reagents; carbon disulfide of at least 99 % (stable for 2–3 years at −20 °C), methanol, concentrated hydrochloric acid (1.16 g/ml), concentrated sulfuric acid (1.84 g/ml), sodium hydroxide solution 100 g/l, methanolic potassium hydroxide solutions I (28 g/l) and II (56 g/l), tin(II) chloride solution 40 g/100 ml in concentrated hydrochloric acid, working tin(II) chloride–hydrochloric acid solution 3.3 g/100 ml (20 ml of tin chloride solution, 20 ml of concentrated hydrochloric acid and carefully 200 ml of water); CS2 stock solution — about 1 ml (about 1.25 g) of carbon disulfide into a 50 ml flask with 40 ml of methanol weighed to the nearest 10 mg before and after the addition, made up with methanol; standard solution — dilutions 1 : 25 and 1 : 100, 1 ml ≈ 10 µg CS2; both are prepared freshly for each calibration curve. Apparatus (5): thoroughly cleaned glassware (cleaning according to 5.1 of prEN 12393-1:1998); decomposition and distillation apparatus (Figure 1) — 1 l or 2 l three-necked round-bottomed flask or a cylindrical flask with a three-necked adapter, dropping funnel, gas inlet tube, ascending Liebig condenser and four absorption tubes connected by spherical joints, the last two preferably with a Widmer helix; flowmeter; heating mantle of at least 450 W or gas burner with a Babo funnel; spectrometer for 270–350 nm with 1 cm quartz cells, preferably double-beam; low vacuum pump at the last absorption tube or a source of nitrogen under pressure at the inlet tube. Sampling (6): the laboratory sample is prepared according to a generally recommended method so as to obtain a representative part; according to a note, sampling procedures for official control of pesticide residues in fruit and vegetables are given in Directive 79/700/EEC. Preparation of samples (7): a sample arriving frozen is stored at −20 °C; fresh samples are analysed where possible immediately after arrival, and wholly or extensively spoiled samples are not analysed; only the portion to which the maximum residue limit applies is taken, and removed plant parts are recorded; if the analysis cannot be done immediately, the sample is stored at 0–5 °C for no longer than 2 days, and for longer storage deep-frozen at −20 °C in portions sufficient for one analysis; reduction of the sample is to give representative portions (e.g. quartering and selecting opposite quadrants; small units — thorough mixing; large fruit and vegetables — wedge-shaped sections, cucumbers — cross sections including the outer surface of each unit); according to a note, residues of dithiocarbamates and thiuram disulfides on the surface of plant parts, not systemic, decompose rapidly, especially in chopped samples. Test portion (7.2): up to 200 g, weighed to ± 1 %; parts interfering with the analysis are removed after weighing (e.g. stones of stone fruit), and the calculation is based on the mass of the original test portion (with stones); the portion is not cut into pieces smaller than needed to pass the neck of the flask, because the more it is cut, the lower the residues; after cutting it is analysed immediately. Procedure (8): warning — many dithiocarbamates, thiuram disulfides and carbon disulfide are toxic by various routes of exposure, especially in concentrated form (manufacturer’s safety data sheets); vapours of some solvents are toxic and readily absorbed through skin — effective fume hoods (8.1). Blanks (8.2): reagent and matrix blanks and spiked recovery tests at levels appropriate to the MRLs, which shall give satisfactory results; the absorption of the reagent blank at 302 nm against KOH solution I shall be zero or near zero; according to notes, the analyst should master the method before analysis, and some vegetables (e.g. Cruciferae) contain natural compounds releasing CS2 under the conditions of the standard, which can give false positive results. Calibration curve (8.3): 5 ml of KOH solution II in each of sixteen 10 ml flasks, two flasks each with 0.1, 0.2, 0.4, 0.8, 1.2, 1.6, 2 and 4 ml of standard solution (1, 2, 4, 8, 12, 16, 20 and 40 µg CS2), made up with methanol, 45 min standing, measurement as in 8.4.3; the curve shall be linear over 1–40 µg CS2 — otherwise a new one is prepared from fresh mixtures; regression on the 16 values may be used instead of a plot. Preparation of the apparatus (8.4.1): first absorption tube — 20 ml of sodium hydroxide solution, second — 20 ml of sulfuric acid, third and fourth (with Widmer helix) — 8 ml each of KOH solution I, cooled with ice water to avoid methanol losses; according to a note, the fourth tube checks complete absorption of CS2; nitrogen or air flow about 150 ml/min through the tubes. Decomposition and distillation (8.4.2): test portion of up to 200 g (400 g for baby food) in the flask, apparatus closed without CS2 losses, 240 ml of tin(II) chloride–hydrochloric acid solution through the dropping funnel (more for bulky material such as lettuce, so that the portion is fully immersed); rapid heating to boiling — especially for deep-frozen material, the solution is heated to boiling before careful addition — and boiling for a total of 30 min; then the KOH tubes are disconnected and the gas flow turned off. Measurement (8.4.3): the contents of the third and fourth tubes are transferred separately to 10 ml flasks, rinsed with KOH solution I, made up with it, and after 15 min the solution from the third tube is measured at 272, 302 and 332 nm in a 1 cm cell against KOH solution I; corrected absorption A_corr = A302 − (A272 + A332)/2.

STATUS (as of 03.10.2026). The PKN search (query “PN-EN 12396-3”, 03.10.2026) returns one result: PN-EN 12396-3:2002 (Polish version, “Wprowadza: EN 12396-3:2000 [IDT]”) without a withdrawal note. In the iTeh catalogue (read on 03.10.2026) EN 12396-3:2000 has the status “Published”, stage 90.93 (decision to confirm the standard).

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 12396-3 appears in 5 records at 5 laboratories: AB 492, AB 519, AB 1205, AB 1334, AB 1748. In the current PCA documents (read on 03.10.2026, issues from 26.11.2025 to 03.07.2026) the number appears in 5 rows — one at each; in each of the five documents the number of page markers equals the number of PDF pages, without repetitions; a search of all 1291 PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy (17 laboratories in the register have no link to a scope document on BIP). Form “PN-EN 12396-3:2002” (AB 492, AB 519, AB 1205, AB 1748) and “PN-EN 12396- 3:2002” with a space after the hyphen (AB 1334). None of these items is suspended. The “Laboratories” tab (query “PN-EN 12396-3”) shows 4 laboratories — all except AB 1334, where the number is written with a space — checked with a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Test object: food of plant origin, agricultural products — with high water content, with high acid and water content, with high starch and/or protein and low water and fat content (AB 492); samples of food of plant origin — with high water content, with high acid and high water content, with high starch and/or protein and low protein and fat content (as written in PCA) — and cereal products for children (AB 519); food of plant origin, fruit and vegetables with high water content, fruit with high acid and water content, food with high starch and/or protein and low water and fat content (AB 1205); fruit and vegetables, fresh or frozen (AB 1334); food (AB 1748, item in a flexible accreditation scope). Characteristic: dithiocarbamate residues expressed as or converted to CS2 (AB 492, AB 519 — together with thiuram disulfide, AB 1334, AB 1748 — “dithiocarbamates (thiuram disulfide)”), residues of pesticides of the dithiocarbamate group (AB 1205). Ranges: (0.01–0.80) mg/kg (AB 492), (0.01–0.2) mg/kg CS2 (AB 519), (0.03–2.0) mg/kg (AB 1205), (0.025–7.500) mg/kg (AB 1334); AB 1748 gives no range. Technique: spectrophotometric method (AB 492, AB 519, AB 1748), UV spectrophotometric method (AB 1205, AB 1334).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. At the sample: surface residues decompose rapidly, especially after chopping — the portion is not cut finer than the flask neck requires and is analysed immediately after cutting (7.1, 7.2). At storage: 0–5 °C for at most 2 days, longer only deep-frozen in portions for one analysis (7.1). At mass: the calculation is based on the mass of the portion before stones are removed (7.2). At the matrix: cruciferous vegetables may release CS2 themselves and give false positive results (8.2, Note 2). At glassware and reagents: glass containers only, no contact with plastics and rubber (4.1). At absorption: the fourth tube checks that CS2 was completely absorbed; the KOH tubes are cooled with ice water (8.4.1). At calibration: linearity 1–40 µg CS2, fresh standards for each curve (4.11, 4.12, 8.3). At the result: the method gives the group sum as CS2, without indicating which compound was present (1).

WHAT WE DO NOT GIVE. We did not read the calculation of the result (9), the confirmatory tests (10), the precision data (11, Annex A) or the test report requirements (12). We do not give maximum residue levels.

Method principle

A food test portion (up to 200 g) is boiled for 30 min with tin(II) chloride solution in hydrochloric acid, which releases carbon disulfide from dithiocarbamates and thiuram disulfides. A carrier gas (about 150 ml/min) carries CS2 through the condenser and traps with sodium hydroxide and sulfuric acid into cooled tubes with methanolic potassium hydroxide, where potassium xanthogenate is formed. The absorption is measured at 302 nm with base line correction at 272 and 332 nm and related to a 1–40 µg CS2 calibration curve; the result is the sum of residues as mg CS2/kg.

Applications

• Low-level residues of dithiocarbamate fungicides and thiuram disulfide (e.g. mancozeb, maneb, propineb, thiram, zineb) as a sum in CS2 (1)
• Foods of plant origin for which low maximum residue levels have been set (1); baby food — 400 g portion (8.4.2)
• Fruit and vegetables, plant foods with high water, acid or starch and protein content, cereal products for children — items in the accreditation scopes of 5 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN 12396-3:2002

Title (PL)

Żywność o niskiej zawartości tłuszczu — Oznaczanie pozostałości ditiokarbaminianów i disiarczku tiuramu — Część 3: Metoda ksantogenianowa z wykorzystaniem spektrometrii UV

Title (EN)

Non-fatty foods — Determination of dithiocarbamate and thiuram disulfide residues — Part 3: UV spectrometric xanthogenate method

Step-by-step procedure

1. Sample and portion

   Portion to which the MRL applies; storage at 0–5 °C up to 2 days or −20 °C; portion up to 200 g, cut only to the size of the flask neck, analysed immediately (7). PN-EN 12396-3:2002 without a withdrawal note (03.10.2026).

2. Calibration and blanks

   16 solutions 1–40 µg CS2 in KOH II, 45 min, linear curve; reagent and matrix blanks, recovery at MRL level (8.2, 8.3).

3. Preparing the apparatus

   NaOH, H2SO4 and 2 × KOH I in the tubes, ice cooling, gas about 150 ml/min (8.4.1).

4. Decomposition and distillation

   Portion in the flask, 240 ml SnCl2–HCl through the funnel, rapidly to boiling, 30 min in total (8.4.2).

5. Measurement

   Tubes 3 and 4 separately to 10 ml flasks, made up with KOH I, after 15 min absorption at 272, 302 and 332 nm, A_corr (8.4.3).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Dithiocarbamates, thiuram disulfides and carbon disulfide are toxic by various routes of exposure, especially when concentrated — manufacturer’s safety data sheets (8.1)
• Vapours of some solvents are toxic and readily absorbed through skin — effective fume hoods (8.1)

Frequently asked questions