COMPARATIVE-STUDY OF 3 DIGESTION METHODS FOR THE DETERMINATION OF CD,CU, AND PB IN CRUDE HERBAL DRUGS PRIOR TO ANALYSIS BY FAAS

A comparison is made of three digestion methods (ashing, wet, and auto clave) for the determination of Cd, Cu, and Pb in crude herbal drugs p rior to analysis by flame atomic absorption spectrometry. It was found that the autoclave digestion method combined with the nitric acid dec omposition procedure was less time-consuming, safer, and provided best recoveries for the three elements. The detection limit for these elem ents ranged from 0.8 mug/L for Cd to 209 mug/L for Pb. Linearity (y = 0.999) was shown to be 5 ppm for Cd, 10 ppm for Cu, and 100 ppm for Pb . Repeatability of the analyses was expressed as the coefficient of va riation, ranging from 0.72-0.90%. Interference effects were not signif icant.