Influence of chemical vapor generation conditions on spectroscopic and analytical characteristics of a hyphenated CVG-ICP system

Abstract

Excitation conditions of inductively coupled plasma hyphenated with chemical vapor generation with the use of borane reducing agents (NaBH₄, C(CH₃)₃NH₂–BH₃ and (CH₃)₂NH–BH₃) and acids (HCl and CH₃COOH) were investigated. The electron number density, the Mg II/Mg I intensity ratio as well as the Ar, B, Bi, Sb and H excitation temperatures were measured at various concentrations of the reductants and acids. Some analytical figures of merit were also determined. The plasma parameters were affected if NaBH₄ was applied. Influence of other borane reductants was not so significant. Hydrogen produced due to chemical vapor generation was responsible for changes in the ICP characteristics, while a role of other products transported simultaneously to plasma was negligible. The Ar, B, Bi and Sb excitation temperatures were independent or slightly dependent on chemical vapor generation conditions. The electron number density increased with NaBH₄ concentration, from 0.7 × 10¹⁵ cm⁻³ for “dry” argon plasma to 1.5 × 10¹⁵ cm⁻³ while the Mg II/Mg I intensity ratio varied from 5 to 11. At low concentrations of the reductants and acids, the plasma was not in robust conditions. If the NaBH₄ was the reductant, the H temperature varied more significantly, from 3100 to 2100 K.