Direct Aerosol Introduction in Constant-Temperature Furnace Atomic Absorption Spectroscopy

Abstract

Combination of a sample introduction/desolvation system with a Woodriff-type constant temperature furnace atomizer allows for the rapid, direct analysis of aqueous samples with precisions comparable to and detection limits 5 times lower than those obtained by conventional flame analysis. The introduction system consists of a pneumatic nebulizer, a spray chamber for collection of large aerosol particles, a heated chamber for solvent evaporation, and a condenser for solvent removal. Under optimized operating conditions, detection limits obtainable for Ag, Cd, Zn, and Pb are 0.14, 0.50, 0.64, and 8.3 ppb, respectively, whereas precision at a concentration level 50 times the detection limit is 2.7%, 5.3%, 7.0%, and 5.5% relative standard deviation. The system is relatively free from chloride and nitrate matrix interferences, whereas interferences resulting from the presence of 1% sulfate and phosphate ions appear to be related to the nebulization process and can be greatly reduced by modification of these conditions.