| Abstract
| - On-line thin-layer chromatographic separation and electrospray mass spectrometry (TLC/ESI-MS) has beenaccomplished by direct linking of a commercial overpressure TLC instrument, OPLC 50, and a Q-TOF massspectrometer. Mass spectrometric detection sensitivityand chromatographic resolution achieved by this configuration were assessed using acidic glycolipids as examples. Under the optimized conditions, a sensitivity of5 pmol of glycosphingolipid was readily demonstrated forTLC/ESI-MS and 20 pmol for TLC/ESI-MS/MS product-ion scanning to derive the saccharide sequence and longchain base/fatty acid composition of the ceramide. Initialpreconditioning of TLC plates is necessary to achieve highsensitivity detection by reducing chemical backgroundnoise. Plates can be used repeatedly (at least 10 times)for analysis, although this may result in a minor reductionin TLC resolution. Following solvent development, separated components on the TLC plates can be detected inthe conventional way by nondestructive staining or UVabsorption or fluorescence and can be stored for on-lineTLC/ESI-MS analysis at a later stage without reductionin mass spectrometric detection sensitivity and chromatographic resolution. Aspects for further improvement ofOPLC instrumentation include use of narrower TLC platedimensions and refined design of the eluate exit system.
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