Application of isotopic-spectral method for determination of carbon and sulphur in silicate materials

Isotopic balancing of carbon and sulphur is carried out in temperature ranges 1500-1900 K and 700-800 K, respectively. Relative intensities of electron-vibrational band heads of 13CO/12CO and 34SO/32SO molecules excited in HF electrodeless discharge in the quartz capillaries are measured. Isotopic concentration is determined. Experimental conditions are optimised and the ratio of analytical signal to background (quantity and pressure of analysed gas, degree of its dilution by inert gas etc.) is improved. Carbon in natural and synthetic silica as well as C and S in geological samples are determined. Limits of detection of C and S concentrations is ∼ 10-5 and ∼ 10-4 % mass., respectively. A precision 5-10 % RSD is achieved in the concentration range from ∼ 10-4 to ∼ 10-3 % mass. (author)