Changes in the Uv Absorption of Silica Containing Aliphatic Moieties after Thermal Modification, and the Quantitative Relationship between the Changes and the Organic Group Content

This paper reports an experiment performed to provide data for examination of the relationship between changes of stationary phase UV spectra as a result of thermal modification by heating at 165°C for 60 min and the content of alkyl groups. The results of a study on the quantitative relationship between coverage density of the silica matrix of a TLC-type stationary phase with an aliphatic moiety and its UV absorption after thermal modification are presented. Statistical analysis of the data obtained reveals a relatively high correlation between the increase in absorption and the paraffin oil content of impregnated RP-2 TLC plates. This report shows that evaluation of the aliphatic moiety content capable of aromatization in an impregnated stationary phase or on modified silica can be obtained solely by use of instrumentation typical of a TLC laboratory.