Using ⁷⁸Ar₂⁺ as the internal standard (argon internal standard) in glow discharge mass spectrometry (GDMS) was investigated in detail. After comparing ion intensities and interferences, i.e. of argon ions, bi-atom argon ions and tri-atom argon ions, the ⁷⁸Ar₂⁺ was selected as the internal standard in the analysis. Mass spectral behavior of the argon internal standard affected by glow discharge current and voltage were studied. The ion intensity relationship between the argon internal standard and the matrix internal standard showed that the argon internal standard and the matrix internal standard have the same corrective effect on sample analysis. The experiment proved that the effects of the difference in analysis samples and the fluctuation of discharge conditions for analytical results were efficiently reduced if the argon internal standard was used. Moreover, the argon internal standard is similar to the matrix internal standard in correcting analytical results and both give satisfactory results. Elemental content in samples can be accurately determined by using the argon internal standard when the matrix content is unknown with good results.

Keywords: argon internal standard, glow discharge mass spectrometry