Overview
Banyen validated a differential pulse anodic stripping voltammetry method for zinc, cadmium, lead and copper and applied it to nine vegetables bought at a Bangkok fresh market in 2011. The paper is mostly method validation; only its Table 8 results are used here. Cadmium ranged 0.01 to 0.06 and lead 0.01 to 0.24 ug/g fresh weight, all below the Thai food standards cited. The article is in Thai with an English abstract, has no DOI, and its peer review is unverified.
Key numbers
- Spring onion lead 0.24 ± 0.00 ug/g fresh weight; winged bean lead 0.12 ± 0.00 (Table 8, p. 96).
- Yardlong bean and sesbania flower cadmium 0.06 ± 0.00 ug/g fresh weight (Table 8, p. 96).
- Broccoli cadmium 0.05 and lead 0.04 ug/g fresh weight (Table 8, p. 95).
Methods (brief)
Edible parts washed, oven-dried at 70 C, ground, digested in sulfuric acid with hydrogen peroxide; DPASV with standard addition in potassium chloride and sodium acetate electrolyte. Spike recoveries roughly 86 to 115 percent; no certified reference material. One market sample per vegetable, results on fresh weight.
Evidence Fitness
Single samples from one market, so the data are illustrative only. The detection-limit figures differ between the English abstract and Thai text, and the vegetables listed in the methods do not match Table 8. Peer review is unverified (non-DOI journal). For vegetables-mixed this is a proxy (individual vegetables, no mixed product).