Trandafir et al. 2012 — Tin in canned foods by ICP-MS

This Romanian study developed and validated an ICP-MS method using microwave acid digestion for determining dissolved inorganic tin (Sn) in canned foods, then applied it to a survey of 14 canned food products (fruit, vegetables, fish) purchased on the Romanian market. The method measures total dissolved tin from tinplate corrosion; it does not speciate organotin compounds (tributyltin, triphenyltin), which require separate GC-ICP-MS or similar workflows. Tin concentrations at the moment of opening ranged from 0.09 mg/kg (canned peas) to 73.68 mg/kg (peeled-tomato-in-juice, solid fraction), all below the EU regulatory maximum of 200 mg/kg for inorganic tin in canned foods (EC No. 1881/2006) and the Codex Alimentarius limit of 250 mg/kg. The study also showed that tin concentrations in syrup can exceed 200 mg/kg within 48 hours of opening when acidic products are stored at 20 °C in the original can.

Key numbers

Analytical performance:

• Limit of detection (tin standard solution): about 0.01 ppb (calculated as 3× standard deviation of blank divided by calibration slope).
• Calibration linearity: R² > 0.9992 over 0–1000 ppb; R² > 0.9995 over 0–15 ppm.
• Accuracy at 0.5 ppm standard: 0.505 ppm found (101% recovery). At 5 ppm standard: 5.12 ppm found (102.4% recovery).
• Repeatability RSD of accuracy standards: 2.42% at 0.5 ppm; 1.87% at 5 ppm.
• RSD of unspiked food samples: 2.2% (fruit cocktail) to 5.8% (peeled tomato).
• Recovery of tin from six spiked canned foods at 25 and 100 ppm spike levels: 91.3–105.2%.

Survey results — tin concentrations in cans just after opening (mg/kg wet weight; mean of six determinations ± SD):

Range across all 14 products and both fractions: 0.09 to 73.68 mg/kg. The maximum permissible level for tin of 200 mg/kg was not exceeded in any can at the moment of opening. Tin concentrations in the solid fraction were consistently higher than in the syrup/liquid fraction, which the authors attribute to surface-absorption capacity of the food matrix. The highest tin levels occurred in acidic, low-pH products (tomatoes, mandarin, pineapple); the lowest occurred in higher-pH vegetables (peas, corn, green beans) and tuna, which the authors note were packed in resin-coated cans.

Post-opening corrosion — tin in syrup of opened cans stored at 20 °C (Figure 1 of source; approximate values read from the bar chart):

After 48 hours at 20 °C, syrup tin concentrations exceeded the 200 mg/kg EU limit in three of the six products tested (mandarin, fruit cocktail, peeled tomato in juice). The authors recommend that consumers transfer the contents of an opened can to a glass vessel immediately after opening.

Regulatory context cited by the authors:

• EU (EC No. 1881/2006): 200 mg/kg maximum level for inorganic tin in canned foods; 100 mg/kg for canned beverages; 50 mg/kg for canned liquid foods for infants and young children.
• FAO/WHO Codex Alimentarius (Procedural Manual, 12th ed., 2001): 250 mg/kg maximum limit for tin in canned foods.
• JECFA Provisional Tolerable Weekly Intake (33rd meeting, WHO Food Additives Series 24, 1989): 14 mg/kg body weight/week for tin (≈ 120 mg/day for a 60 kg person).

Methods (brief)

Instrument: Perkin-Elmer ICP-MS model ELAN 9000. Operating conditions: Rf power 1000 W, fassele-type ICP torch with ceramic alumina injector, cross-flow tip nebulizer at 0.93 L/min, 20 sweeps/reading, 2 readings/replicate, 5 replicates per measurement.

Sample preparation: microwave-assisted nitric acid digestion in a Milestone Microwave Labstation (maximum 1200 W, 100 bar, 200 °C) with 75 mL TFM vessels in a 10-hole heating block. Approximately 2.5 g of sample was placed in each TFM vessel; 5 mL 65% HNO₃ (Fluka 84380) and 2 mL 30% H₂O₂ (Fluka 95302) were added. Heating programme: 80 °C × 5 min at 200 W, 80 °C × 2 min at 200 W, 120 °C × 15 min at 400 W, 120 °C × 2 min at 400 W, 200 °C × 10 min at 600 W, 20 min cooling. Digests were transferred to 50 mL volumetric flasks and brought to volume with ultrapure water from a Basic TWF system; further dilution was applied to bring concentrations within the calibration range. Tin standards were prepared from a 1000 mg/L stock solution (Fluka 96524). Reagent blanks were included in every digestion series.

Replication: each product was sampled across three separate cans from the same production batch, with six analytical determinations per can. Reported values are mean ± standard deviation across the six determinations.

What this method measures and does not measure: total dissolved tin (Sn) including inorganic Sn(II) and Sn(IV). The method does not speciate between stannous and stannic forms, and does not measure organotin compounds (tributyltin, triphenyltin, methyltins, dibutyltin, dioctyltin, etc.), which require derivatisation and chromatographic separation (GC-ICP-MS or LC-ICP-MS) and are chemically distinct from the inorganic Sn that migrates from tinplate.

Implications

• Certification: contributes occurrence data for total inorganic Sn across 14 canned product types, with the strongest signal that acidic products in unlacquered tinplate (tomato, mandarin, pineapple at low pH) carry materially higher Sn than higher-pH vegetables (peas, corn, green beans) and resin-coated cans (tuna). At-purchase concentrations were all below the 200 mg/kg EU and 250 mg/kg Codex regulatory caps for inorganic tin in canned foods.
• Storage-related corrosion: the post-opening kinetics finding (acidic syrups exceeding 200 mg/kg within 48 h of opening at 20 °C) is a behaviour-of-the-product observation; it documents that the EU limit assumes intact storage and that consumer-stage behaviour can move tin concentrations above the regulatory cap independent of manufacturer control.
• Courses: useful illustration of pH-dependent corrosion kinetics in tinplate cans, the lacquer/no-lacquer difference, and the inorganic-Sn-vs-organotin analytical distinction.
• App: among canned categories, acidic fruit cans (citrus, tropical fruit, pineapple) and tomato-based products are higher-expected-Sn than canned neutral-pH vegetables and canned fish in resin-coated cans. Time since opening at room temperature in the original can is an additional risk modifier.

Wiki pages this source may touch

• tin
• canned-tomatoes
• canned-fruit-cocktail
• canned-mushrooms
• canned-green-beans
• canned-corn
• canned-tuna
• canned-vegetables
• canned-fruit
• canned-tomatoes
• canned-fish
• eu-1881-2006-contaminants-superseded
• codex-cxs-193-1995-tin-canned-foods

Verification notes

• 2026-05-20 — Merge-enhance pass against the source PDF (raw/Manual Fetch Kimi /02_Vegetables_and_Vegetable_Products/02_Vegetables_and_Vegetable_Products/Determination of Tin in Canned Foods by Inductively Coupled Plasma-Mass Spectrometry.pdf). Prior page (updated 2026-05-13) had the following defects, all corrected here:
  • raw_handle: was generic manual-fetch-kimi; updated to MFK_determination-of-tin-in-canned-foods-by-inductivel per current MFK_ convention.
  • raw_path: was truncated (...Plasm.pdf); restored to the full PDF filename.
  • sample_n was 13; the source’s Table 3 lists 14 distinct canned products (four pineapple brands A/B/C/D plus mandarin, fruit cocktail, carrots, mushrooms, two peeled-tomato brands A/B, peas, green beans, corn, tuna). Corrected to 14.
  • ingredients: previously listed invalid slugs (tomatoes, mushrooms, peas are not in the current taxonomy snapshot dated 2026-05-18). Replaced with valid canned-tomatoes, canned-mushrooms, and dropped the bare peas entry; added canned-green-beans, canned-corn, and canned-tuna for the matching canned-product analogues that exist in the taxonomy. The earlier [[ingredients/beans]] and [[ingredients/corn]] (bare-form fresh ingredients) were replaced with the canned-form ingredient slugs to match what was actually measured.
  • products: added canned-tomatoes to the existing trio (canned-vegetables, canned-fruit, canned-fish) since two of the 14 products tested are specifically peeled-tomato-in-juice cans, which the existing canned-tomatoes product page should claim.
  • The “Wiki pages updated on ingest” legacy heading was renamed to ## Wiki pages this source may touch per the current schema.
  • The “Wiki pages updated on ingest” list referenced [[regulations/eu-1881-2006-sn-canned-foods]], which does not exist in the current taxonomy. Replaced with the existing slugs [[regulations/eu-1881-2006-contaminants-superseded]] and [[regulations/codex-cxs-193-1995-tin-canned-foods]].
  • The Implications section previously read “For HMT&C purposes: canned food is an important Sn exposure route…” — that phrasing crossed into wiki/HMT&C-firewall territory by framing the paper’s contribution in HMT&C-program terms rather than in literature terms. Rewritten to describe what the paper contributes as occurrence data without HMT&C-program framing.
  • Added an explicit “What this method measures and does not measure” paragraph in Methods to lock in the inorganic-Sn-only scope and rule out organotin claims.
  • Added the post-opening corrosion table (read from Figure 1 of the source) so downstream pages can see the storage-time kinetics without re-reading the PDF.
  • Added near_duplicates: [] to satisfy current schema.
• Numerical fidelity spot check: every value in Table 3 (14 products × 2 fractions × pH × years-since-manufacture) was cross-checked against the PDF Table 3 image; all values match. The accuracy standards (0.505 ppm at 0.5; 5.12 ppm at 5; RSD 2.42% and 1.87%) match the source. The JECFA PTWI (14 mg/kg BW/week, ≈ 120 mg/day for 60 kg), EU 1881/2006 (200/100/50 mg/kg), and Codex (250 mg/kg) limits all match the source.
• Speciation discipline: paper measures total dissolved Sn; it does not separate Sn(II) from Sn(IV), and does not measure organotins. metals: [Sn] is correct (the bare Sn abbreviation covers total inorganic tin; the dedicated [[metals/tin-inorganic]] slug exists but the umbrella Sn matches how the source reports values). The Methods section explicitly disclaims organotin coverage so downstream pages do not over-interpret.
• Brand firewall: the source labels its four pineapple cans and two peeled-tomato cans as A/B/C/D and A/B with no brand names; no brand-by-brand attribution is required or possible from the source. Methods names instrument vendors (Perkin-Elmer ELAN 9000, Milestone Labstation), reagent vendors (Fluka, Riedel-de-Haën), and the water-system vendor (Basic TWF) — these are scientific-method vendor names and are explicitly permitted under the 2026-05-17 Part 12 carve-out.
• Routing: matrices: [canned-food] covers the analytical matrix; product slugs cover the four canned-product categories the source touches (canned-vegetables, canned-fruit, canned-tomatoes, canned-fish). jurisdictions: [RO, EU] because the survey is Romanian-market and the regulatory frame cited is EU plus Codex.
• 2026-05-20 — Audit subagent verdict REVISE; one ❌ on Check 2 (slug vocabulary): [[ingredients/canned-vegetables]] was not a valid ingredient slug (the slug exists only as a product slug under wiki/products/, not as an ingredient page under wiki/ingredients/). Verified against ls wiki/ingredients/canned-*.md — confirmed no canned-vegetables.md ingredient page exists. Finding applied: removed the invalid [[ingredients/canned-vegetables]] entry from the ingredients: frontmatter array and from the “Wiki pages this source may touch” section. The specific canned-ingredient slugs already in the page (canned-corn, canned-green-beans, canned-mushrooms, canned-tomatoes, canned-fruit-cocktail, canned-tuna) cover the canned vegetables actually measured. Checks 1, 3, 4, and 5 were ✅; no other findings to apply.

2026-06-08 byte-identical filesystem-copy enhancement: added a near_duplicates entry recording the Kimi agent’s June 8 placement of the same PDF under raw/Manual Fetch Kimi /June 8/Kimi_Agent_Download Corruption Issue/_extracted_02_Vegetables_and_Vegetable_Products/02_Vegetables_and_Vegetable_Products/. SHA-256 verified byte-identical to the canonical raw_path (cf02363493b9f24ba353e181ba3ac7fac20dea26b5356fec7584283be8fe8862); the same hash also appears at three other Kimi-corruption-issue paths (May 21 .../papers/02_Vegetables_and_Vegetable_Products/, June 8/.../papers/02_Vegetables_and_Vegetable_Products/, and manual-fetch/Kimi_Agent_Download Corruption Issue/papers/02_Vegetables_and_Vegetable_Products/). Manual-fetch loop now recognizes the June 8 _extracted_ location as already-ingested. No claim, value, slug, exposure number, key-numbers, or HMTc-firewall change. No new audit cycle spawned because no body or evidence-bearing frontmatter changed.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.