Automatic on-line preconcentration system for graphite furnace atomic absorption spectrometry for the determination of trace metals in sea water

Abstract

An automatic on-line preconcentration system for graphite furnace atomic absorption spectrometry (GFAAS) for the determination of trace metals in sea water was developed. This system was modified from a Perkin-Elmer AS-40 autosampler by mounting a silica gel C 18 microcolumn near the tip of the automsampler capillary. The preconcentration procedure was performed by using the pumps of the AS-40 autosampler and a four-way valve and controlled by a programmable controller. The chelating agent ammonium tetramethylenedithiocarbamate [ammonium pyrrolidinedithiocarbamate APDC)] was added to the sample solution and only 0.2–2 ml of sample was required to determine cadmium and copper in sea water. The calibration graph method was used and the detection limits of cadmium and copper were 1.26 and 6.5 ng l −1, respectively.