Characterisation of a Microwave-induced Plasma Atomic Emission Spectrometry System Using a Modified Plasma Torch Coupled With Pneumatic and Hydraulic High-pressure Nebulization

Abstract

The analytical potential of a modified plasma torch was examined by the determination of Cr, Fe and Mn in aqueous solutions. The microwave-induced plasma was sustained in a rectangular-type TE ₁₀₁ cavity with a power of 500 W. Argon was used as the plasma gas. Sample introduction was carried out by using a pneumatic nebulizer coupled with a cyclone spray chamber and also by using a hydraulic high-pressure nebulizer. A computer-controlled monochromator with background correction was used for detection of the emission lines of the analytes. The detection limits of the analytes varied from 0.09 to 0.97 µg ml ^-1 . The short-term stability and long-term precision were measured by monitoring the intensity of the Mn 279.482 nm line ( n =10) and were found to be 3 and 4%, respectively. The excitation and gas temperatures of the microwave induced plasma were evaluated using Fe atoms and OH ^- radicals as thermometric species. The temperatures obtained with Boltzmann plots were 4600±230 and 2500±60 K, respectively.