Online combustion followed by carbon dioxide removal: evaluation of a new approach for the analysis of volatile organic substances by inductively coupled plasma optical emission spectrometry

Abstract

A novel online combustion system was developed for the quantification of metals (Ag, Cd, Cr, Fe, La, Li, Mg, Ni, Pb, Y, Zn, and Zr) in volatile organic solvents such as acetone, methyl isobutyl ketone (MIBK), chloroform, dichloromethane, tetrachloroethane or trichloro-trifluoroethane. After combusting the sample aerosol in a commercial carbon analyzer oven in an oxygen-rich atmosphere, carbon dioxide and remaining oxygen were removed from the gas stream prior to the introduction into an inductively coupled plasma optical emission spectrometer (ICP-OES). The proposed combustion/carbon removal approach allowed stable operation of the ICP even when introducing highly volatile solvents that otherwise would have immediately extinguished the plasma. Analyte signals in halogenated solvents were found to be significantly higher than in non-halogenated ones and non-linear calibration functions were observed for all investigated analytes below 5 mg kg⁻¹. Though a stable operation of the plasma was possible, the analyte signal intensities obtained in water were, depending on the element and the solvent, between 1.5 and 2800 times higher than in halogenated solvents.