CONCENTRATION OF TRACE-ELEMENTS IN WATER SAMPLES BY REDUCTIVE PRECIPITATION

The use of borohydride reduction as a means of preconcentrating elements by precipitation as the element or as a boride has been explored. It has been shown that the optimized procedure reproducibly effects the precipitation of all 18 elements studied; only four of these exhibited recoveries less than 90%. The general ease of use, the demonstrated accuracy and precision, the high preconcentration factors available, the self-cleansing properties of the primary reagent, the granular character of the precipitate, and the possibility of direct analysis of the precipitate are all factors to recommend this approach.