Neglected Applications of Monolithic Structures: Advanced Thin Layer Chromatography-Mass Spectrometry Approaches

Abstract

Thin-layer or planar chromatography (TLC) continues to evolve, albeit at a slower pace than its more powerful counterparts, liquid and gas chromatography. This is easy to understand as TLC has always been a very simple alternative to these methods without the need for complex instrumentation. This does not mean, however, that TLC cannot be combined with sophisticated detection methods such as mass spectrometry or performed in multiple dimensions. To make TLC more widely applicable, its separation potential is constantly being improved. Therefore, layers with new chemical compositions and innovative processes are being developed leading to layers that enable applications not yet described. This review describes the use of monolithic layers formed from porous organic polymers developed for use in mass spectrometry with laser desorption and ionization without the participation of a low molecular weight matrix or for the preparation of layers with unconventional formats for separations in two dimensions. Attention is also given to so far unusual approaches where TLC is realized in microfluidic environments.