DETERMINATION OF CADMIUM IN BIOLOGICAL-MATERIALS BY TUNGSTEN COIL ATOMIC-ABSORPTION SPECTROMETRY

A simple, low cost tungsten coil furnace was evaluated for electrothermal atomic absorption spectrometry (ETAAS). The open atomizer was resistively heated by using a power supply with a voltage feedback circuit. The analysis time using a manually injected sample volume of 10 mul was 41 s. Acceptable precision (relative standard deviation <3%, n = 12 at 1.0 ng ml-1 of cadmium) was obtained for cadmium values ranging from 0.5 to 6.0 ng ml-1. The characteristic mass for peak height absorbance was 0.5 pg. Results compare well with certified values of different biological materials digested with nitric acid. For certain reference materials better accuracy was obtained from data based on integrated absorbance.