Abstract
Chromium(VI) anions (chromates, dichromates) react with lead acetate in an acetic acid solution to form a yellow precipitate of lead chromate. To a 100 cm3 of a sample solution containing less than 500 μg of chromium(VI), 1cm3 of acetic acid and 1cm3 of 5% lead acetate solution were added at 5°C. The solution was stirred for 10 min and filtered through a O.2pm membrane filter paper. The precipitate on the paper was subjected to the X-ray fluorescence spectrometry. The calibration curve gave a curved line in the region of 50-500 μg of chromium (1/1), but a straight line in 1-50 μg only for the direct addition of O.5 g of a crys talline lead acetate.
