Anomalous temperature dependence of gas chromatographic retention indices of polar compounds on non-polar stationary phases

摘要

Increasing the reliability of both GC and GC-MS identification requires appropriate interlaboratory reproducibility of gas chromatographic retention indices (I). Known temperature dependence, I(T), is the main source of non-reproducibility of these parameters. It can be approximated with a simple linear function I(T). However, since mid-1990s beginning of 2000s some examples of anomalous temperature dependence, I(T), preferably for polar analytes on non-polar stationary phases were revealed independently by different authors. The effect implies the variations in the sign of the temperature coefficients beta=dI/dT for selected compounds and, hence, the appearance of the I-extrema (usually, minima).