Selected Bottlenecks of Densitometric Detection with Chiral Analytes
Modern applications of thin layer chromatography (TLC) should inevitably benefit from the best-standardized and best-performing materials and equipment. The phenomenon of a slight deviation of the analytes’ migration tracks from strict verticality has been long recognized and well described in the TLC literature, and it is almost omnipresent in TLC. This chapter presents a selection of such unpredictable effects, which sometimes accompany enantioseparations and in certain specific cases can even make such separations impossible. The results provide a preliminary molecular-level insight into the retention mechanism of 2-Arylpropionic acids in the chiral thin layer chromatographic systems with l-arginine as chiral selector. Formation of keto-enols as intermediates in many organic reactions is known to be vigorously catalyzed in the basic environment and effectively hindered in the acidic one. The recommended solution is to scan the relatively broad bands on the respective chromatograms instead of a narrow lane along the supposed straight-line migration track of the analytes.