Dry ash-voltammetric determination of cadmium, cooper, lead, and zinc in foods
Jones, J.W.; Gajan, R.J.; Boyer, K.W.; Fiorino, J.A.
Journal - Association of Official Analytical Chemists 60(4): 826-832
1977
ISSN/ISBN: 0004-5756 PMID: 893306 Document Number: 114449
An analytical method is presented for determining cadmium, copper, and lead by differential pulse anodic stripping voltammetry and zinc by cathodic scan differential pulse voltammetry. Food samples are dry ashed using a sulfuric acid ashing aid, dissolved in dilute nitric acid, buffered at pH ~ 4.3 with an acetate buffer, and quantitatively analyzed using the technique of standard additions at a hanging mercury drop electrode. The quantitation limits (5 times the estimated detection limits) are approximately 5 ng/g for Cd, Cu, and Pb, and 50 ng/g for Zn. Accuracy of the method is established by (a) analysis of NBS Standard Reference Material No. 1577 Bovine Liver, (b) comparison of results obtained by the method described with those obtained by independent analytical methods, and (c) quantitative recovery of analyte metals from fortified, non-canned food samples. Results from an interlaboratory method trial indicate that the method is suitable for the analysis of a variety of food types.