Characterization of a Modified, Low-Power Argon Microwave Plasma Torch (MPT) as an Atomization Cell for Atomic Fluorescence Spectrometry

Abstract

A microwave plasma torch (MPT) has been newly modified and used as an atomization cell for atomic fluorescence spectrometry (AFS). The analytical performance of the MPT-AFS system has been characterized with hollow cathode lamps (HCLs) working in the pulsed mode as an excitation source and a pneumatic nebulizer for aqueous sample introduction. The method exhibits a relatively large dynamic range over at least three orders of magnitude in concentration and fairly good precision in a range from 0.42% (Zn) to 4.9% (Ag). It was found that observation height, microwave power, and plasma support-gas flow rate have an important influence on the performance of MPT-AFS. The detection limits obtained by the new MPT-AFS system are in a range from 0.25 (Cd) to 121 (As) ng/mL for ten elements examined. A comparison of MPT-AFS with other plasma AFS approaches suggests several advantages of the MPT source as an atomizer for AFS.