Fast heated ballast furnace atomizer for atomic absorption spectrometry Part 2. Experimental assessment of performances

Abstract

The theoretical predictions concerning atomization efficiency in the fast heated ballast furnace atomizer were examined by determination of Pb in the organic and inorganic matrices using a Quantum Z.ETA atomic absorption spectrometer. The instrument provided fast heating of the tube atomizer (10 K ms⁻¹) and temperature stabilization on the pre-set level. In the experiments the tube was furnished with compact ballast (e.g., a graphite rod 1 mm in diameter and 5–9 mm in length or other refractive materials of similar volume and configuration). The samples were injected into the tube, disregarding their exact location on the wall or ballast. It is shown that in the employed ballast furnace for the sampling volumes below 10–15 μl the vapor release into the gas phase occurs after interim condensation on the ballast. For the samples of tetraethyllead, base oil and lead nitrate respective analytical signals are observed after stabilization of tube temperature (below 2673 K), independent of the volatility of the analyte and level of temperature setting. High gas phase temperature provides, for those samples, complete recovery of the analyte without involvement of chemical modifiers. The reduction of spectral background from sea-water matrix at Pb determination and behavior of analytical signals for In and Cr confirm common mechanism of sample vapor release via interim condensation on the ballast. The optimization of material for the ballast is still needed taking into consideration physical properties and the chemical activity of its surface towards the sample vapor.