Solvent extraction and flameless atomic absorption determination of arsenic in biological materials

This method for the determination of arsenic specifies wet digestion of biological materials, followed by reduction of arsenic(V) to arsenic(III) and extraction of arsenic(III) with diethylammonium diethyldithiocarbamate (DDDC) in chloroform. The extract is analyzed by flameless atomic absorption spectrometry (AAS). Recoveries of arsenic from plant and animal tissues ranged from 88 to 108%, averaging 99%. Analyses of rat tissues, using a radioisotope technique, averaged 103% of theoretical. Repeatability studies on rat tissues showed the method to be consistent with coefficients of variation ranging from 3.0 to 8.5%, and a test for ruggedness showed that the method is not affected by slight variations in procedure, but is affected by the presence of Fe and Cu. The method is sensitive to about 0.04 microgram arsenic in the total digest (injections of 20 muL of a 4 ng/mL solution).