Wu et al. 2021 - ETAAS measurement of Pb and Cd in edible salt and soy sauce
Wu and coauthors developed an ETAAS method using fluorescent carbon nanoparticles as a matrix modifier for Pb and Cd in high-salt foods. The paper includes measured blank-sample values and spike recoveries for edible salt and soy sauce, so it is limited occurrence evidence as well as a method-validation source. It should be used cautiously because the study design is analytical-method validation rather than a market survey.
Key numbers
The abstract reports LODs of Pb 0.0140 mg/kg in edible salt and 0.0470 mg/kg in soy sauce, and Cd 0.0015 mg/kg in edible salt and 0.0005 mg/kg in soy sauce. Table 2 reports blank and spiked sample results:
| Matrix | Metal | Unspiked found | Spiked found | Recovery |
|---|---|---|---|---|
| Edible salt | Pb | 0.021 mg/kg | 1.030 mg/kg after 1.00 mg/kg addition | 101.0% |
| Edible salt | Cd | 0.017 mg/kg | 0.110 mg/kg after 0.10 mg/kg addition | 93.0% |
| Soy sauce | Pb | 0.013 mg/kg | 0.480 mg/kg after 0.50 mg/kg addition | 93.4% |
| Soy sauce | Cd | 0.012 mg/kg | not fully visible in extracted table | not fully visible in extracted table |
The authors report precision of 0.19-0.85% RSD and recovery of 93.0-101.0%.
Methods (brief)
The method uses electrothermal atomic absorption spectrometry with fluorescent carbon nanoparticles as a matrix modifier to reduce high-salt matrix interference. Linearity was 10-50.0 ug/L for Pb and 0.4-4.0 ug/L for Cd.
Implications
Certification: Useful for salt and soy-sauce method context and limited occurrence values, but not a broad benchmark survey.
Courses: Demonstrates the matrix-interference problem in high-salt food testing.
App: Can support a low-confidence high-salt-food evidence note if synthesis admits method-validation samples.
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Verification notes
The fetched filename correctly identifies salt Cd context, but the paper also covers soy sauce and Pb. The soy-sauce Cd spiked row was truncated in the extracted text and should be checked against the rendered PDF during audit before extracting a recovery value.
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.
| Commit | Date | Description |
|---|---|---|
| 50ec0f0 | 2026-05-30 | ingest auto-fetched 2026-05-30 2145 batch 1: 10 source pages |