SEAGOING METHOD FOR THE DETERMINATION OF CHROMIUM(III) AND TOTAL CHROMIUM IN SEA-WATER BY ELECTRON-CAPTURE DETECTION GAS-CHROMATOGRAPHY

A seagoing method for the determination of Cr(III) and total chromium in sea water is presented. The method employs electron-capture detection of the volatile trifluoroacetylacetone derivative of Cr(III) formed via solvent extraction with toluene; total chromium is determined as Cr(III) after reduction. Detection limits at sea are 0.062 and 0.255 nM for Cr(III) and total chromium, respectively. Accuracy for total chromium was verified by the analysis of standard reference materials from the National Research Council of Canada. The procedure has a precision of 1.3% at 4.7 nM total chromium, and has been applied to stored samples in the laboratory in addition to its use at sea.