Troncoso and Guzman 1988 — Metallic contaminants in Andalusian vinegars

This early study measured Fe, Zn, Cu, Pb, and total As in 16 white wine vinegar samples from Western Andalusia, Spain, using direct flame atomic absorption spectrophotometry (FAAS) without prior digestion (the authors verified that no interfering components plug the flame at the working acetic-acid concentrations). The authors report no important metallic contamination overall; only one sample exceeded the Spanish regulatory limit of 1 ppm for total (Pb + As). The study is described in the abstract as the first systematic characterization of metallic content in Andalusian vinegars.

Key numbers

All values in ppm (mg/kg) as reported. To convert to µg/kg (ppb), multiply by 1000.

Iron (n=16): range 1.95–19.66 ppm; mean 8.44 ± 0.07 ppm. The paper notes the threshold for “hazy phenomena” in vinegar is approximately 10–15 ppm Fe. Two samples (no. 8 at 16.37 ppm and no. 9 at 19.66 ppm) exceeded 15 ppm, although no cloudiness was observed in either. Five samples in total exceeded 10 ppm Fe (no. 2, 7, 8, 9, 10). No sample exceeded the FAO/WHO Codex draft (1982) Fe limit of 30 mg/kg.

Zinc (n=16): range 0.51–36.90 ppm; mean 7.86 ± 0.51 ppm. Highly variable. 25% of samples (no. 1, 2, 3, 13) exceeded 10 ppm; sample 3 reached 36.90 ppm.

Copper (n=16): range 0.07–6.14 ppm; mean 1.35 ± 0.04 ppm. All samples below the Codex draft (1982) individual Cu limit of 10 mg/kg.

Zn + Cu combined (Spanish regulation ≤ 10 ppm total): 63% of samples (10 of 16) within the combined Spanish limit; 6 samples exceeded it (no. 1, 2, 3, 9, 10, 13).

Lead (n=16): range 0.20–1.21 ppm; mean 0.55 ± 0.05 ppm (= 550 µg/kg). Per-sample Pb values from Table 3 (ppm): 0.39, 0.44, 0.63, 1.21, 0.43, 0.39, 0.80, 0.59, 0.53, 0.65, 0.27, 0.76, 0.48, 0.78, 0.32, 0.20. Only sample 4 (1.21 ppm) exceeded the Codex draft (1982) Pb limit of 1 mg/kg.

Arsenic (n=16, total As): range 0.039–0.242 ppm; mean 0.136 ppm. No sample exceeded 0.3 ppm (the OIV limit for wines, cited by the paper for comparison; no agency limit for total As in vinegar is invoked).

Combined Pb + As (Spanish regulation ≤ 1 ppm total): only sample 4 (1.21 + 0.242 = 1.452 ppm) exceeded the Spanish combined limit, consistent with the abstract’s statement that only one sample exceeded 1 ppm total Pb + As.

Correlation: moderate correlation between Cu and Fe (r = 0.685) at the concentrations measured.

Regulatory context cited by the paper: Spanish regulations (Código Alimentario Español, 1967): total Zn + Cu ≤ 10 ppm; total Pb + As ≤ 1 ppm. FAO/WHO Codex Alimentarius draft (1982, “Draft European Regional Standard for Vinegar”): Pb 1 mg/kg, Cu 10 mg/kg, Zn 10 mg/kg, Fe 30 mg/kg (individual per-metal limits). US Department of Agriculture (Schroeder & Lythgoe 1941): max admissible Pb in cider vinegar = 3.5 ppm. OIV: 0.3 ppm As ceiling for wines.

Methods (brief)

Flame atomic absorption spectrophotometry on a Perkin Elmer 2380 with air–acetylene flame. Liquid vinegar samples analyzed directly without digestion; the authors checked that no flame-plugging components were present. Samples were classified into three groups by acetic-acid content (3%, 7%, 8%) and calibration standards were prepared in matching aqueous acetic-acid matrices to minimize matrix effects. Wavelengths and band passes (Table 1): Zn 213.9 nm / 0.7 nm (lamp 15 mA); Cu 324.8 nm / 0.7 nm (30 mA); Fe 248.3 nm / 0.2 nm (30 mA); Pb 217.0 nm / 0.7 nm (10 mA). Air 16 L/min; acetylene 2 L/min; burner height 8 cm; integrating time 3 s. Arsenic was determined by AAS with a volatile hydride generator (Perkin Elmer MSH 10): wavelength 193.7 nm; band pass 0.7 nm; air–acetylene cell heating; 3% sodium borohydride + 1% sodium hydroxide reducing mixture; 11 s integrating time; arsenic content calculated by standard addition. Sodium content was determined by flame emission to assess interference on iron; Fe/Na ratio was in all cases > 0.01. Reagents: analytical-grade hydrochloric, acetic, nitric and sulphuric acids, sodium borohydride, lead nitrate, metallic copper, metallic zinc, metallic iron, arsenic oxide (Merck). Stock solutions 1000 ppm (Cu, Fe, Pb, As) and 500 ppm (Zn). Evidence tier B reflects the 1988 publication date, small n (16), direct-injection FAAS without acid digestion, and total-arsenic measurement without iAs speciation.

Implications

Certification: Provides a historical baseline for Andalusian (Sherry-region) white wine vinegar. Lead mean 550 µg/kg, range 200–1210 µg/kg; one sample of 16 (6%) exceeded the Codex draft Pb limit of 1 mg/kg. Total arsenic mean 136 µg/kg, range 39–242 µg/kg, with no inorganic-arsenic speciation — modern HMTc threshold work in vinegar requires iAs speciation that this dataset does not provide.

Courses: Illustrative of how direct-injection FAAS without digestion can be applied to liquid acidic matrices when matrix-matching the calibration standards. The 1988 publication date, small n, and lack of acid digestion mean the absolute values are best treated as historical context rather than as a contemporary occurrence dataset.

App: For Andalusian (Sherry-region) wine vinegar in this 16-sample set — Pb 200–1210 µg/kg range with mean 550 µg/kg; total As 39–242 µg/kg with mean 136 µg/kg; Cu, Zn, Fe variable and largely within the Codex draft per-metal limits.

Verification notes

Page was originally drafted under the legacy manual-fetch-kimi handle and last updated 2026-05-14. Merge-enhanced on 2026-05-28 against the source PDF (v2 skill autonomous ingest) to:

• Replace legacy raw_handle: manual-fetch-kimi with the canonical MFK_metallic-contaminants-in-andalusian-vinegars handle.
• Add raw_sha256: 859e8b195eff1d32772fb606ae3928c691172469441120a5765ed857e756768b (was missing).
• Correct the Cu range minimum from 0–6.14 ppm to 0.07–6.14 ppm. Sample 2 (the prior minimum-by-rounding) has Cu = 0.07 ± 0.00 ppm per Table 2; no sample is at exactly 0 ppm.
• Correct the iron exceedance count from “Three samples exceeded the Fe limit associated with ‘hazy phenomena’ (>10–15 ppm)” to “Two samples exceeded 15 ppm (no. 8 and 9)” per the explicit statement on page 745: “no type of hazy phenomena was observed in those samples exceeding 15 ppm for iron (samples no. 8 and 9).” Added the broader “5 samples >10 ppm” count for completeness (no. 2, 7, 8, 9, 10) and the Codex Fe ceiling of 30 mg/kg (no exceedances).
• Split the previously-conflated “Spanish/Codex limit for total Zn + Cu is 10 ppm” into the two distinct citations the paper actually makes: Spanish regulation = Zn + Cu combined ≤ 10 ppm (Código Alimentario Español 1967); Codex draft 1982 = Cu 10 mg/kg AND Zn 10 mg/kg individually (per-metal, not combined). Re-grouped the Zn/Cu/combined statements accordingly.
• Added the mean Cu uncertainty (± 0.04 ppm) from Table 2, previously omitted.
• Added the explicit list of samples exceeding each combined Spanish limit (Zn + Cu: 6 samples; Pb + As: 1 sample) for traceability.
• Added the per-sample Pb list from Table 3 (kept; the existing list was accurate) and added the sample-4 As + Pb arithmetic (1.21 + 0.242 = 1.452 ppm) to make the abstract’s “only one sample exceeded 1 ppm Pb + As” claim numerically traceable.
• Removed the cross-source synthesis sentence “Pb in wine vinegar approximately 200–1200 µg/kg range across both this and Acosta 1993 data” from the App section per CLAUDE.md Part 2 (the source page reports this paper’s findings only; cross-paper comparison belongs in synthesis pages, not source pages).
• Trimmed the prior “unlike the later Ndung’u 2004 work that established digestion requirements” comparison from the Methods evidence-tier rationale per CLAUDE.md Part 2 (same reason). Tier-B rationale retained without the cross-source comparison.
• Expanded Methods section with the Table 1 instrumental parameters (lamp intensities, band passes, gas flows, integrating times), hydride-generator settings for As, reagents and stock-solution concentrations, and the Fe/Na ratio interference check — all already present in the PDF, previously summarized at a level that omitted reproducibility-relevant detail.
• Added ## Verification notes section (previously absent).
• Set updated: to 2026-05-28.
• Preserved cite_key, raw_path, license, doi: null / no_doi_assigned: true, metals, ingredients, products, matrices, jurisdictions, sample_n, near_duplicates from the prior revision.

Brand firewall (Part 12): the paper does not name commercial brands; samples are identified only by number (1–16) and region (Sherry / El Condado / aged Sherry). No Part 12 concern.

Speciation (Part 14): arsenic is reported as total arsenic (hydride generation following standard addition); the page uses tAs in metals: accordingly. Mercury, chromium speciation, and other HMTc analytes were not measured by this paper.

Wiki pages updated on ingest

• vinegar
• wine-vinegar
• lead
• arsenic
• copper
• zinc
• iron

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.