ABSTRACT
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Coupling of planar chromatography to mass spectrometry (MS) integrating an additional chromatographic separation step by high-performance liquid chromatography (HPLC) is a special technique of linking high-performance thin-layer chromatography (HPTLC) to MS. The integration of HPLC offers a second, orthogonal dimension concerning selectivity, as HPTLC is almost performed on normal-phase silica gel plates and HPLC usually on reversed-phase C18 columns. By this strategy, the separation efciency of “only” HPTLC can be outperformed and the high versatility of HPTLC can clearly be shown [1]. Concerning the MS detection process, various ion sources such as electrospray ionization (ESI), atmospheric pressure chemical ionization, or atmospheric pressure photo ionization can be used, depending on the analytes under focus. In food analysis, ESI is by far the most used ionization technique in nearly each eld of application for polar, semipolar, and even quite nonpolar analytes.
