Determination of Cd, Cr and Pb in Polyethylene Resin by Inductively Coupled Plasma Atomic Emission Spectrometry after Open System Wet Decomposition Using a Mixture of Nitric Acid and Sulfuric Acid

A new sample-preparation method was proposed for the determination of cadmium (Cd), chromium (Cr) and lead (Pb) in polyethylene resin by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The polyethylene resin sample was decomposed by using a mixture of nitric acid and sulfuric acid. The bumping was reduced by using a new type of watch glass with a stem. The precipitation of PbSO4 was dissolved by an aqueous solution of 20∼25% ammonium acetate/acetic acid. The standard reference materials of resin (BCR-680, BCR-681) were analyzed to verify the proposed method. The obtained results for Cd, Cr and Pb by this method were in good agreement with their certified and reference values.