ELIMINATION OF ALUMINUM INTERFERENCE IN ARSENIC DETERMINATION AT THE 193.7-NM LINE USING ZEEMAN BACKGROUND CORRECTION AND PLATFORM ATOMIZATION

River sediment samples containing 13-24% Al2O3 were analyzed for parts per million levels of arsenic using the 193.7-nm line. Experiments we re carried out using Zeeman background correction and platform atomiza tion in the presence of palladium as a matrix modifier. Sensitivity wa s greatly enhanced with the use of the platform and the integrated abs orbance for arsenic was nearly constant within the atomization range o f 1700-2000 degrees C. The peak of the relatively volatile arsenic was separated from that of the more refractory aluminium at the above tem perature range, leading to the decrease in background absorption. The characteristic mass, m(0), and detection limit of arsenic were found t o be 18 pg and 30 pg, respectively, under optimal experimental conditi ons. Arsenic in river sediment samples was determined by slurry atomiz ation; the results obtained agreed favorably with the reference values .