🍎 Determination of silver, arsenic, cadmium, cobalt, chromium, copper, manganese, molybdenum, nickel, lead, selenium, thallium, uranium and zinc in foodstuffs by ICP-MS — the sample is pressure-digested with nitric acid according to EN 13805 (low-water foods after adding water), the digest made up (e.g. to 20 ml) and usually diluted tenfold, and the elements measured with an argon-plasma mass spectrometer, with an internal standard (e.g. Rh, In, Lu), calibration in the linear range and interference removal by a collision or reaction cell, MS/MS or high resolution; result as total content in mg/kg or mg/l, PN-EN 17851

Food chemistry PN-EN 17851

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of SIST EN 17851:2023 (English text of EN 17851:2023): from the European foreword through Clauses 1–8 to 9.2 (limits of quantification, with the list of factors) on page 11. Outside the sample remain the rest of 9.2 (example calculation of the limit), precision, test report and annexes (including isotopes and interferences — A, interlaboratory study data — B) and the bibliography.

ACCORDING TO THE TEXT OF EN 17851:2023. The standard was prepared by CEN/TC 275 “Food analysis — Horizontal methods”, whose secretariat is held by DIN; national implementation was due by January 2024 at the latest. Scope (1): determination of Ag, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl, U and Zn in foodstuffs by ICP-MS after pressure digestion; the interlaboratory study analysed: banana (deep-frozen), cocoa powder, wheat noodle powder, currant nectar (deep-frozen), milk powder, oyster (dried), celery (dried), dogfish liver (dried), liver (deep-frozen) and kale (dried); Table 1 — ranges analysed (lowest and highest content in the ten matrices, mg/kg): arsenic 0.02–36.6, lead 0.004–0.58, cadmium 0.006–15.2, chromium 0.06–5.71, cobalt 0.03–7.49, copper 0.71–74.0, manganese 0.31–73.5, molybdenum 0.05–1.88, nickel 0.11–11.0, selenium 0.06–8.70, silver 0.011–1.98, thallium 0.008–0.12, uranium 0.003–0.26, zinc 1.8–1582; the lower limit of the range depends on the matrix and water content and is a laboratory-specific value determined for each element when calculating the quantification limit (9.2). References (2): EN 13804, EN 13805, EN 15765, EN 17264. Terms (3): none. Principle (4): the sample is pressure-digested according to EN 13805, low-water foods after adding water; in the digest the 14 elements are quantified by ICP-MS — the solution is nebulized, the aerosol enters an argon plasma where the elements are ionized, and the ions pass through a system of cones into a mass spectrometer, separated by mass-to-charge ratio and detected by pulse and/or analogue detector; the result is the total content measured by this procedure, in mg/kg or mg/l; for other elements e.g. EN 15763 may be considered, and aluminium and tin are determined according to EN 17264 and EN 15765. Reagents (5): chemicals, gases and water sufficiently free of the elements determined; nitric acid at least 65 % (about 1.4 g/ml); multi-element stock solution, e.g. 10 mg/l (Ag, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Tl, U) and 100 mg/l (As, Se, Zn), or single-element 1000 mg/l suitable for ICP-MS and chemically compatible; multi-element standard solution e.g. 0.1 or 1.0 mg/l (stable at least one month, protected from light when containing silver); internal standards — covering the analyte mass range, with similar ionization energy, absent from the sample and free from interference; rhodium, indium and lutetium have proved suitable; scandium is unsuitable (interferences of Ca and Si molecular ions), and internal standards below 100 m/z should not be used; internal standard solution e.g. 10 mg/l (stable at least three months); calibration solutions — at least three concentrations in the linear range, with acid concentration as in the sample solution, fresh each working day — e.g. 0.5, 1 and 2 µg/l (As, Se, Zn ten times higher), with internal standard 10 µg/l, and a zero-point solution; the internal standard can also be added via a separate pump channel with a Y-piece. Apparatus (6): equipment in contact with the sample and solutions cleaned according to EN 13804; vessels of quartz, PFA, FEP or polypropylene are recommended, not releasing or absorbing elements; ICP-MS with argon plasma, sample introduction and nebulizing system, control and data acquisition, able to eliminate or minimize interferences (reaction and/or collision cell, tandem MS, resolution above 4000). Sampling (7): not part of the procedure; contamination and losses of analytes are to be avoided. Digestion (8.1): with nitric acid, low-water foods after adding water, according to EN 13805; after the spontaneous reaction the vessel is closed and the digestion started; conditions depend on the manufacturer, sample reactivity, vessel pressure resistance and temperature; according to a note, silver recovery depends on chloride content — adding HCl may help but introduces interferences; the digest is made up (e.g. to 20 ml) and measured directly or after dilution — a dilution factor of 10 is recommended, at least 2.5; all solutions have similar acid concentration and the same internal standard concentration as the calibration solutions. ICP-MS conditions (8.2.1): about 20–30 min stabilization, optimization with a solution of e.g. Mg, Rh, Pb and Ce (10 µg/l) — oxide and doubly charged ion rates should be below e.g. 3 %; with a collision or reaction cell the gas flow is optimized taking the matrix into account, and the internal standard measured under the same conditions; with different resolutions — mass windows centred and at least one internal standard at each level; detector mode transitions must be continuous. Determination (8.2.2): recommended isotopes in Annex A, free from interferences; interferences removed by collision/reaction cell, higher resolution or correction equations (with simultaneous measurement of uncorrected signals); curve from the zero-point and calibration solutions; for complex matrices and high salt, standard addition can be advantageous; the linear range is checked regularly; dilutions with the same acid and internal standard concentration; if the internal standard signal drops by more than 20 %, the solution is diluted further, and if it rises by more than 20 % the cause is sought (e.g. cone deposits, internal standard present in the sample); high salt (usually > 0.1 %) causes deposits and memory effects — adequate flushing, checked with the zero-point solution, and the internal standard signal may drop by up to 30 %; the calibration is checked e.g. every ten samples. Quality control (8.3): in each series, samples with reliably known contents through the whole procedure from digestion, and blanks for each digestion series; a certified reference material of similar matrix and concentration is recommended. Calculation (9.1): ω = a · V · F / (1000 · m) in mg/kg (or / v in mg/l), where a — content in the solution in µg/l, V — volume of the made-up digest in ml, F — dilution factor, m — sample mass in g; blank subtraction is not recommended — with contamination affecting results the whole series is discarded and the cause eliminated. Quantification limit (9.2): calculated for each element, depending among others on the calculation procedure, matrix and water content, sample mass, digest volume, vessel materials, chemical purity, instrument, technique and laboratory environment.

STATUS (as of 03.10.2026). The PKN search (query “PN-EN 17851”, 03.10.2026) returns one result: PN-EN 17851:2024-01 (English version, “Wprowadza: EN 17851:2023 [IDT]”) without a withdrawal note. In the iTeh catalogue (read on 03.10.2026) EN 17851:2023 has the status “Published” (stage 60.60 — definitive text made available).

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 17851 appears in 11 records at 3 laboratories: AB 438 (9), AB 509, AB 519. In the current PCA documents (read on 03.10.2026, issues from 26.11.2025 to 01.10.2026) the number appears in 4 rows — 2 at AB 438 (each reference there covers several consecutive items) and one each at AB 509 and AB 519; in each of the three 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 17851:2024-01” (AB 438, AB 509) and “PN-EN 17851” without year (AB 519). None of these items is suspended (in the AB 438 and AB 509 documents the suspensions concern other items marked in bold italics). The “Laboratories” tab (query “PN-EN 17851”) shows all 3 laboratories — checked with a tab query on the labcoda.pl production server on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). AB 438 — lead, cadmium, arsenic and nickel in nine food groups: cereals and cereal products, non-alcoholic beverages, additives and processing aids; nuts and oilseeds, sweets including chocolate, fruit and vegetables and their products; algae and prokaryotes; foods for special nutritional purposes in liquid form; fish, seafood and products; herbs and spices, mushrooms; coffee, tea, cocoa and meat and dairy substitutes; sugars, syrups, honey, meat and milk; food supplements — with ranges from (0.002–2.500) mg/kg (cadmium in liquid foods) to (0.044–45.000) mg/kg (nickel in algae). AB 509 — food (cereals, fruit, vegetables, fish, meat, sweets, milk, infant and young child formulae, supplements, tea, cocoa, herbs, spices): lead (0.010–10.0), cadmium (0.005–10.0), nickel (0.10–10.0), arsenic (0.005–10.0) mg/kg. AB 519 — food, metal content, item in a flexible accreditation scope. Technique: ICP-MS at all.

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. At interferences: a spectrometer able to eliminate interferences is needed (cell, MS/MS or resolution > 4000), and isotopes free from interference are chosen (6.2, 8.2.2). At the matrix: dilution at least 2.5-fold (10 recommended), and a drop in internal standard signal of more than 20 % requires further dilution (8.1, 8.2.2). At the internal standard: not scandium and not masses below 100 (5.4). At silver: recovery depends on chlorides (8.1, note). At the blank: it is not subtracted — a contaminated series is repeated (9.1). At calibration: fresh solutions each day, checks e.g. every ten samples (5.6, 8.2.2). At the quantification limit: the laboratory determines it for each element and matrix (1, 9.2). At the range: the interlaboratory study covered e.g. lead only up to 0.58 mg/kg (Table 1), while laboratories state upper limits up to 10 mg/kg.

WHAT WE DO NOT GIVE. We did not read the example calculation of the quantification limit, the precision data, the list of isotopes and interferences (Annex A) or the detailed interlaboratory results (Annex B). We do not give maximum levels of elements in food.

Method principle

The food sample is pressure-digested with nitric acid according to EN 13805 (dry samples after adding water), the digest is made up to a fixed volume and diluted (tenfold recommended) with an internal standard added. The solution is nebulized into the argon plasma of the ICP-MS, and the ions of the 14 elements are separated by m/z and detected, with interferences removed by a collision or reaction cell, MS/MS or high resolution. Concentrations are read from a curve of the zero-point and at least three calibration solutions, and the content ω = a · V · F / (1000 · m) in mg/kg.

Applications

• Ag, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl, U and Zn in foodstuffs — total content (1, 4)
• Interlaboratory study: banana, cocoa, wheat noodles, currant nectar, milk powder, oysters, celery, dogfish liver, liver, kale (1)
• Lead, cadmium, arsenic and nickel in cereals, fruit, vegetables, fish, meat, milk, infant food, supplements, herbs and algae — items in the accreditation scopes of 3 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN 17851:2024-01

Title (PL)

Artykuły żywnościowe — Oznaczanie pierwiastków śladowych i ich form chemicznych — Oznaczanie zawartości Ag, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl, U i Zn w artykułach żywnościowych techniką spektrometrii mas z plazmą wzbudzoną indukcyjnie (ICP-MS) po mineralizacji ciśnieniowej

Title (EN)

Foodstuffs — Determination of elements and their chemical species — Determination of Ag, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl, U and Zn in foodstuffs by inductively coupled plasma mass spectrometry (ICP-MS) after pressure digestion

Step-by-step procedure

1. Digestion

   HNO3 under pressure according to EN 13805 (dry food with water); making up, 10× dilution (8.1). PN-EN 17851:2024-01 without a withdrawal note (03.10.2026).

2. ICP-MS tuning

   20–30 min, optimization: oxides and 2+ ions < 3 %, cell gas matched to the matrix (8.2.1).

3. Calibration

   Zero-point and ≥ 3 standards with internal standard; check about every 10 samples (5.6, 8.2.2).

4. Measurement

   Interference-free isotopes; monitoring the internal standard signal (± 20 %), flushing after salty samples (8.2.2).

5. Control and result

   Reference material and blanks in each series; ω = a · V · F / (1000 · m); LOQ determined by the laboratory (8.3, 9).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Nitric acid and pressure digestion — vessels and conditions according to the manufacturer’s instructions (8.1)

Frequently asked questions