CLEAN ROOM AND MICROWAVE DIGESTION TECHNIQUES - IMPROVEMENT IN DETECTION LIMITS FOR ALUMINUM DETERMINATION BY GF-AAS

A rapid, precise, and accurate method for the determinaton of aluminum in part-per-billion concentrations in biological materials using graphite-furnace atomic absorption spectroscopy has been developed. In order for the necessary accuracy and precision for the analysis of aluminum in bone and brain tissue could be obtained, reduction of laboratory environmental contributions to the aluminum blank was requried. Use of a closed-vessel microwave digestion system and a clean room for sample preparation accomplished this goal by reducing Al concentrations in the digestion blanks from 10 ppb to 1 ppb. Digestion time was decreased from many hours to several minutes, and the amount of acid required for digestion was reduced by 70%. Using less nitric acid improved precision in the analyzed solutions by significantly extending the lifetime and consistency in perfomance of the graphite tube atomizer.