Determination of Lead and Cadmium in Fish and Clam Tissue by Atomic Absorption Spectrometry with a Molybdenum and Lanthanum Treated Pyrolytic Graphite Atomizer

摘要

A molybdenum and lanthanum treated pyrolytically coated graphite tube is employed for the furnace atomic absorption spectrometric determination of lead and cadmium directly in nitric-perchloric acid tissue digests. Lanthanum tends to promote the formation of a smooth lead atomization peak for aid in peak quantitation. Both molybdenum and lanthanum help reduce chemical interference and interference from uncompensated background signals during analyte atomization. Under typical conditions, the average analytical recoveries are within the 90-110% range for both lead and cadmium, and peak height reproducibility is about 2-3% when working sufficiently above detection limits. Accuracy of the method is assessed by analyzing the NBS SRM 1577 bovine liver standard and performing alternate determinations by anodic stripping voltammetry.