Determination of low levels of cadmium in marine and fresh water sediments by graphite furnace atomic absorption spectrometry employing a reduced palladium chloride modifier and by inductively coupled plasma atomic emission spectrometry

Abstract

A method of determining low concentrations of cadmium in marine and fresh water sediments utilizing a reduced PdCl₂ chemical modifier for graphite furnace atomic absorption spectrometry (GFAAS) is presented. National Research Council of Canada marine sediment reference materials BCSS 1, MESS 1 and PACS 1 along with National Institute of Standards and Technology Standard Reference Materials 1645 and 1646 were used to determine the precision and accuracy of the method using various palladium-modifier concentrations. The modifier concentration must be approximately 4000 mg l^–1 to be effective. The chemical modifier GFAAS method was compared with inductively coupled plasma atomic emission spectrometry (ICP-AES) in the analysis of 199 coastal marine sediments. No evidence of a systematic difference between the two data sets was found at the 95% confidence level. The mean 1σ scatter in the method comparison, from 0.8 to 5.0 µg g^–1, is ± 0.27 µg g^–1. The ICP-AES limit of detection is degraded from 0.5 to 0.8 µg g^–1 by the uncertainty in the sediment inter-element corrections, implying a mean inter-element correction uncertainty of ± 2.5%.