Overview
Beltrán and colleagues optimized and validated two total reflection X-ray fluorescence (TXRF) methods, one for lead, arsenic and chromium and one for mercury, and applied them to six commercial dietary supplements from Mexico and Spain. The paper is mainly a methods study; it prints per-gram results for four Mexican products and digest-solution results for two Spanish products compared against ICP-OES.
Key numbers
- Fat burner supplement (A-01): lead 1.12, arsenic 0.65, chromium 13.62 µg/g; mercury not detected (Section 3.5).
- Laxative supplement (A-02): lead 1.32, arsenic 0.37, chromium 13.69 µg/g; mercury not detected (Section 3.5).
- Mercury: tejocote root supplement 0.42 µg/g, omega oil supplement 0.12 µg/g (Section 3.5).
Methods (brief)
About 0.02 to 0.05 g of sample was digested with nitric acid, hydrochloric acid and hydrogen peroxide at 80 °C for eight hours, then measured by TXRF with a gallium internal standard. Solution LODs were 0.41 to 0.75 µg/L. Accuracy was checked with BCR-610 groundwater CRM, spike recoveries of 91 to 108%, and an ICP-OES comparison.
Evidence Fitness
Only six products, chosen for popularity, with triplicate analyses. The per-gram values are given in text without dispersion, and the Spanish products are reported only as solution concentrations. Useful mainly as method context with a few occurrence values; the vitamin-mineral-premix page is not linked because none of the products is a vitamin or mineral premix.
Related evidence
Update history
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