Determination of Carbon in Carbonate-Silicate Glasses by X-Ray Spectral Microanalysis

A method for determining carbon content in carbonate-aluminosilicate glasses using X-ray spectral microanalysis has been proposed and implemented. To account for the contribution of the non-useful signal from the conductive carbon layer and carbon deposits formed under the electron probe to the analytical signal of the CKα line, a calibration curve was constructed using carbonate standard samples with varying carbon content. The analytical signal was based on the calculated area under the first peak of the CKα line, which allowed consideration of the influence of chemical bonds formed by carbon with oxygen and other elements on the shape and position of the CKα line. Optimal conditions for recording X-ray spectra in the CKα line region were selected for subsequent carbon determination. Linear calibrations obtained at 5 kV using carbonate standards are highly reproducible, with a relative standard deviation (sr) of analytical signal values ranging from 1–3%. The calculated detection limits for carbon using the developed method are 0.2–0.4 wt.%, with the lower limit of quantifiable content being 0.6–1.2 wt.%.