Calibration of the thermal desorption-gas chromatography-mass spectrometry system using standards generated in the process of thermal decomposition of chemically modified silica gel

A calibration method for the thermal desorption gas chromatographic-mass spectrometric (TD-GC-MS) determination of n-propanethiol based on a gas standard mixture generated in the process of thermal decomposition of chemically modified silica gel is proposed. The experimental results indicated that the total amount of n-propanethiol liberated from unit mass of the gel did not depend on the total mass of the gel used. A calibration curve for the TD-GC-MS system for n-propanethiol, determined for the relationship between the mass of n-propanethiol and the mass of the modified silica gel used, was found by a linear regression method and was characterized by a correlation coefficient r=0.99. This means that the amounts of liberated n-propanethiol are directly proportional to the mass of the modified gel used within the examined range of masses of silica gel samples. Consequently, the amount of the analyte (n-propanethiol) can be determined on the basis of mass of silica gel used and hence the modified silica gel can be treated as a standard of the liberated component (n-propanethiol) in this case).