Combination of flow injection analysis with flame atomic-absorption spectrophotometry: determination of trace amounts of heavy metals in polluted seawater

Abstract

A simple flow injection system, the FIAstar unit, was used to inject samples of seawater into a flame atomic-absorption instrument allowing the determination of cadmium, lead, copper and zinc at the parts per million level at a rate of 180–250 samples per hour. Further, on-line flow injection analysis pre-concentration methods were developed using a microcolumn of Chelex-100 resin, allowing the determination of lead at concentrations as low as 10 parts per 10⁹(p.p.b.) and 1 p.p.b. for cadmium and zinc. The sampling rate was between 30 and 60 samples per hour and the readout was available within 60–100s after sample injection; the sampling frequency depended on the pre-concentration required.