A Thermal Vaporizer-Capacitively Coupled Microwave Plasma System for Trace Hg Determination

Abstract

A system has been constructed, which couples a new type of thermal vaporizer to a capacitively coupled microwave plasma (CMP). It is used to determine trace levels of Hg in water. A sample solution of 2-7ml is jetted onto a fused silica wool heated to 630-945°C and thermally vaporized. A large volume of the resulting steam is removed by a highly efficient double coaxial wall condenser. The desolvated mercury solute enters the CMP; 253.65 nm emission is monitored. Basic system characteristics studied include vaporizer temperature, gas flow rates, detection limits, dynamic range and matrix effects. Linear calibration curves are obtained for concentrations ranging from 1 to 1000 μg/l.