Simultaneous Multielement Determination of Trace Metals Using 10 mL of Seawater by Inductively Coupled Plasma Atomic Emission Spectrometry with Gallium Coprecipitation and Microsampling Technique

By use of a 10-mL sample, the concentrations of several trace elements In seawater were determined simultaneously by Inductively coupled plasma atomic emission spectrometry. The techniques employed were copreclpitation with gallium hydroxide and microsample Introduction. A preconcentration factor of 200 times was achieved by dissolving gallium precipitate with 50 μL of nitric acid. The solution of one drop size (50 μL) was introducedInto the plasma via a cross-flow nebulizer. Integration time and sample volume were examinedIn detail for the optimization of the measurement conditions of the microsampling technique. With internal standardization using gallium, the concentrations of Al, TI, Cr, Mn, Fe, Co, Nl, Cu, Zn, Y, and Pb were determined. The detection limits of these elements ranged from 500(Pb) to 10 ng/L (Cu and Zn). The precisions of most elements for unacidified coastal seawater are about 10%, and accuracy for Mn, which Is the only element measurable for an acidified seawater standard, is fairly good. The analytical procedure of the present method Is so simple that about 50 samples could be preconcentrated and analyzed in 1 h. This method was applied to the analysis of some natural seawaters, and it was found that this method was effective, especially for the analysis of seawaters where the available sample volume was very small.