Determination of traces of sulphur by electrothermal evaporation and non-thermal excitation of S-containing species in a hollow cathode discharge (FANES/MONES) and in a microwave induced plasma (MIP)

Abstract

The determination of sulphur by emission of S-atoms, S+ ions, S2 and CS molecules using sulphate and other ions was investigated in such non-thermal excitation sources as the normal atmospheric argon-MIP and glow discharge in FANES/MONES (Furnace Nonthermal Excitation Spectrometry/Molecular Nonthermal Excitation Spectrometry). In both cases electrothermal evaporation (ETE) of the sample is applied. In the MIP technique (ETE-MIP) electrothermal evaporation from a new tungsten coil system is used and in the FANES samples are brought in the furnace. The thermal, electrical, chemical and pressure conditions were optimized and the emission spectra recorded. Detection limits are 90 ng for the ETE-MIP technique using the S 469.413 nm atom line. With the tungsten tube-FANES/MONES detection limits of 17 ng are obtained with S2 molecular band at 383.73 nm. With FANES/MONES in a carbon tube and measurements on CS molecular bands a detection limit of 2 ng is obtained.