Comprehensive two-dimensional gas chromatography with a rotating thermal desorption modulator and independently temperature-programmable columns

In comprehensive two-dimensional gas chromatography, two individual separat ions are coupled by means of a rotating thermal desorption modulator interf ace. The injection pulse introduced via the interface onto the second colum n should be as short as possible. Parameters affecting the modulator operat ion are studied. In the setup used in this study, the temperature of the se cond column can be programmed independently from that of the first column. Optimization of the second-dimension separation to minimize peak broadening and maximize resolution is discussed and an elegant approach to determine second-dimension retention times using a non-constant modulation frequency is demonstrated. The high separation power of the comprehensive system is d emonstrated by the analysis of technical and biota samples containing chlor inated biphenyls and toxaphene.