ABSTRACT

The overall performance of a separation method is intrinsically linked to the performance of the detector used as part of the system. Other handbook chapters detail principles, operation, and applications of common detectors for thin-layer chromatography (TLC), many of which have been in use since the beginnings of TLC. In contrast, mass spectrometry (MS), especially in an imaging mode, is a relatively new detection method for TLC. Mass spectrometry has been used with gas chromatography and liquid chromatography, and with supercritical fluid chromatography and capillary electrophoresis, to provide a balanced combination of separation and detection capabilities. Benchtop GC/MS systems (available for about $50,000 USD) are operated directly by the end user. Other low-cost, high-performance chromatography/mass spectrometric combinations will follow with continued development of a new generation of smaller, more automated mass spectrometers. These same technological developments have also led to TLC/MS in several different forms. Moreover, renewed emphasis on the measurement of two-dimensional imaging data from mass spectrometry holds genuine promise for TLC/MS and for planar chromatography coupled with mass spectrometry in general. This chapter summarizes the approaches that have characterized TLC/MS since its first inception through to the more recent one-and two-dimensional imaging systems.