Equivalent characteristic spectrum analysis in TG–MS system

• The novel method can determine the flow rate of evolved gas by mass spectrum.
• The calibration system of the relative sensitivity of different gas is developed.
• As a reference gas, carrier gas is used to calculate the flow rate of evolved gas.
• l The mass spectrum of all gases is separated into that of various components.l The analyzed mass flow rate of evolved gas agreed well with the result from TG.

A novel method of equivalent characteristic spectrum analysis (ECSA) was developed to analyze the mass spectrum of TG–MS system according to the operating principle of TG–MS coupling system. In ECSA, the characteristic spectra and the relative sensitivity were calibrated for all tested gases. This method effectively separated the mass spectrum, eliminated the mass discrimination and temperature-dependent effect, even if there were some overlaps at characteristic peak. Based on the decomposition of CaCO3 and CaC2O4, actual flow rate and concentration of individual component in evolved gas have been dynamically determined. The analyzed mass flow rates of evolved gases agree well with ECSA and the experimental data from TG analysis. Moreover, the stability of calibration and quantitative analysis by ECSA method were discussed.

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