DETERMINATION OF IRON AND ZINC IN ADIPOSE-TISSUE BY ONLINE MICROWAVE-ASSISTED MINERALIZATION AND FLOW-INJECTION GRAPHITE-FURNACE ATOMIC-ABSORPTION SPECTROMETRY

Flow injection was used to develop an on-line automated focused microw ave assisted procedure for the mineralization of adipose tissue and th e determination of iron and zinc by graphite furnace atomic absorption spectrometry. Mineralization of samples was accomplished with a mixtu re of sulfuric and nitric acid and by the alternative exposition of th e sampling unit in the microwave irradiated zone. Additional flows of Triton X-100 and Pd-Mg matrix modifier were introduced to avoid detrim ental accumulation of solids on the wall of the tubing and to minimize matrix interference effects, respectively. Selected aliquots of miner alized samples were introduced with a sampling arm assembly, by means of air dispositive displacement, into the graphite tube atomizer. The entire system was controlled by a computer, independent of the spectro meter. The analysis of adipose tissue containing 2.3-8.6 and 1.5-4.4 m u g g(-1) of iron and zinc, respectively, with good precision and accu racy was possible. The main advantage of the method is that the determ ination of iron and zinc in adipose tissue is performed in a totally c losed system with a minimum of sample manipulation, exposure to the en vironment and minimum operator attention.