Thin layer chromatography coupled with electrospray ionization mass spectrometry for direct analysis of raw samples.

Conventional mass spectrometric analysis of raw samples commonly requires sample pretreatment and chromatographic separation using high performance liquid chromatography or gas chromatography, which could be time-consuming and laborious. In this study, thin layer chromatography (TLC) coupled with electrospray ionization mass spectrometry (ESI-MS) was developed for direct analysis of raw samples. The sorbent material of the TLC plate was found to be able to retain the interfering compounds and allow interested analytes to be extracted, ionized and detected by ESI-MS with much reduced matrix interference. Our results showed that this method could be effectively applied in direct analysis of samples containing common interfering compounds, e.g., salts and detergents, and rapid detection and quantitation of target analytes in raw samples. Offline and online separation and detection of different components in mixture samples, e.g., plant extracts, using TLC-ESI-MS were also demonstrated. Overall, this study revealed that TLC-ESI-MS could be a simple, rapid and efficient method for analysis of raw samples.