Determination of lead in plastic containers for pharmaceutical products by atomic-absorption spectrophotometry using a carbon rod atomiser

Abstract

A method is described for the determination of lead in a variety of plastic pharmaceutical containers by direct solid-sample analysis using a carbon rod atomiser. The recovery of added standard is measured in order to establish suitable assay conditions for each type of plastic. In the absence of recovery tests, low results for lead in the presence of plastics can result from mechanical loss during ashing or because the lead has been rendered more difficult to atomise. The amounts of lead found ranged from about 0.03 to nearly 1 p.p.m., with a mean relative standard deviation of 15%, and were considerably less than the British Pharmacopoeia limit of 50 p.p.m. Where comparative tests were possible, results are shown to be in good agreement with those obtained by measuring lead in a chelate-organic solvent extract of wet-ashed plastic.