Purpose: Our laboratory recently analyzed 11 commercially available spices for trace metals to evaluate aerosol phase dilution for contamination control and lower detection limits.
Methods: Two different brands of spice powders (except annatto powder) were purchased at a local supermarket, prepared in triplicate by hot acid digestion using a mixture of nitric acid and hydrochloric acid, then analyzed by collision cell ICP-MS for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), thallium (Tl), and zinc (Zn). The spices analyzed were annatto powder, cinnamon powder, curry powder, paprika, smoked paprika, and turmeric powder. NIST SRM-1647 (Peach Leaves) was used as a control and standard quality control procedures were followed during the analysis.
Results: Results for the NIST sample were within ±10% of the expected values and all other QA/QC measurements were within target specifications. Measured concentrations were as follows (detection limit, range) - As: 0.007, 0.010 to 0.200 µg/g; Cd: 0.001, 0.012 to 0.294 µg/g; Cr: 0.057, 0.158 to 4.32 µg/g; Cu: 0.021, 1.52 to 13.6 µg/g; Pb: 0.036, 0.051 to 0.470; Mn: 0.041, 9.40 to 168; Tl: 0.001, 0.001 to 0.022 µg/g; Zn: 1.43, 8.04 to 29.1 µg/g.
Significance: Aerosol phase dilution allowed digested samples to be prepared in a low final volume, facilitating lower detection limits while reducing the potential for sample contamination from additional sample handling. While differences by brand were observed, these results indicate exposure to trace metals by consumption of foods prepared using these spices is low, but elements with nutritional value were present in significant concentrations.