Microwave digestion of biological samples with tetramethylammonium hydroxide and ethylenediaminetetraacetic acid for element determination

Abstract

A microwave-digestion system with a closed PTFE vessel was used to improve the leaching of inorganic constituents from biological samples with tetramethylammonium hydroxide (TMAH) and ethylenediaminetetraacetic acid (EDTA). The effects of microwave parameter settings and the quantities of TMAH and EDTA used on leaching efficiency were evaluated. This new digestion method has been applied to the standard reference materials NIST SRM 1577 B Bovine Liver, 1515 Apple Leaves and NIES CRM No. 1 Pepperbush, No. 3 Chorella, No. 6 Mussel and No. 7 Tea Leaves. The major and minor elements in the digests were analyzed by flame atomic absorption spectrometry or graphite furnace atomic absorption spectrometry. Good agreement of the analytical results with the certified values was obtained.