Determination of bromide using a helium microwave induced plasma with bromine generation and electrothermal vaporisation for sample introduction

Abstract

A helium microwave induced plasma is utilised for the determination of bromide. The bromide sample solution is either introduced into an oxidation-generation mixture of potassium dichromate-sulphuric acid, or is vaporised electrothermally and then swept into the helium plasma. The microwave induced plasma (MIP) in a TM₀₁₀ cavity excites bromine and the emission measurements are taken at both the Br II 470.5-nm and 478.6-nm lines. The calibration graphs were linear from 5 ng to 50 µg of bromide using the chemical generation technique at both analytical lines, whereas the calibration data from the graphite rod vaporisation sample introduction technique showed a linearity from 5 ng to 10 µg of bromide. Detection limits for both techniques were 1 ng. Fluorine, chlorine and iodine as well as other common anions and cations do not significantly interfere with the measurements, below 100 times the amount determined.