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Heavy metals in whole kernel dent corn determined by atomic absorption

Garcia, W.J., Blessin, C.W., Inglett, G.E.
Cereal chemistry 1974 v.51 no.6 pp. 788
dent corn, food analysis, heavy metals, zinc, lead, copper, cadmium, chromium, manganese, atomic absorption spectrometry, quantitative analysis, food contamination, feed contamination, analytical methods
Whole kernel corn was wet ashed with nitric and perchloric acids, and the resultant salts were dissolved in dilute acid. Concentration levels in corn samples were determined for zinc, manganese, copper, lead, cadmium, and chromium by flame atomic absorption. Because this technique is not sensitive enough to measure the small quantities of mercury present, an oxidation procedure was developed that decomposed organic material in corn at a temperature of 70°C. The mercury was retained effectively in an aqua regia solution until the elemental mercury was de emanated for measurement of the vapor by a nonflame atomic absorption technique. The aqua regia solution ensured that mercury was completely solubilized. In addition, mercury standards prepared in a 10% aqua regia medium have proved to be stable at low concentrations for extended periods. Mean concentration values for the seven metals studied in 11 different corn samples ranged from a high of 23 γ/g for zinc to a low of approximately 0.0024 γ/g for mercury.