Thin-Layer Chromatography Coupled with Mass Spectrometry

Thin-Layer Chromatography and Electrospray Mass Spectrometry Coupled Using a Surface Sampling Probe

“…Thin-layer chromatography (TLC) is a largely mature, but very important general laboratory tool. , In comparison to modern column chromatography alternatives such as high-performance liquid chromatography, TLC is a relatively inexpensive, flexible, and portable method that requires minimal equipment and little method development time. Although not particularly mainstream, much TLC research continues in the areas of separation media or development methodologies as well as in the areas of detection, identification, and quantification methods. , In the latter three areas, the direct coupling of TLC and mass spectrometry (MS) and tandem mass spectrometry (MS/MS or MS n ) are of particular interest because of the low detection levels, molecular identification capabilities, and detection specificity the techniques provide. − …”

“…There are also numerous examples over the last two decades of attempts to couple directly TLC and MS. In those attempts, most of the inlet/ionization systems directly amenable to surface analysis, such as secondary ion mass spectrometry, have been used with varying success. − Matrix-assisted laser desorption/ionization (MALDI) has had the most recent successes in TLC/MS with several notable advances coming from the laboratory of Hercules and co-workers. − Major obstacles or limitations in using MALDI-MS to couple TLC and MS have been the need for extensive postseparation preparation of the TLC plates prior to analysis, the need for specialized plates, the low-mass spectral noise from the MALDI matrix, and the requirement that the analysis be carried out in the vacuum chamber of the instrument.…”

Analysis of small molecules by ultra thin-layer chromatography-atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry

“…In those cases in which the standard compounds are not available (e.g., the screening of new natural agents or combinatorial chemistry samples), the identification of unknowns has to be performed using a specific technique, such as mass spectrometric detection. The combination of TLC and MS has been a very active research area over the last few years [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. TLC-MS has most frequently been performed as an off-line process in which the sample is scraped and extracted from the plate before MS analysis [5,22,23], or is analyzed as such with the use of various in situ techniques [15, 16, 19 -21, 24 -31], the most common of these being TLC-liquid secondary ion mass spectrometry (LSIMS), TLC-fast atom bombardment (FAB), TLC-matrix-assisted laser desorption/ionization (MALDI), and TLC-surface-assisted desorption/ionization (SALDI).…”

“…Several methods, such as ultraviolet/visible (UV/ VIS), fluorescence, DAD, mass spectrometry (MS), Fourier transform infrared (FTIR), and Raman spectroscopy have been applied for the in situ detection of analyte zones on a TLC plate [12][13][14][15], the most common of these being UV and fluorescence. In qualitative TLC, the identification of the compounds is based on either the color reactions of the separated sample zones or on the comparison of the R F values of the analyte and a standard compound after visualization under a UV lamp.…”

Mass spectrometry analysis of new chemical entities for pharmaceutical discovery

“…Separation combined with MALDI–MS for small molecule analysis has been reported by several authors using ultra‐thin layer chromatography (TLC–MALDI) (Busch, 1992; Somsen, Morden, & Wilson, 1995; Weins & Hauck, 1996; Chen, Shiea, & Sunner, 1998; Wilson, 1999; Gusev, 2000; Mehl & Hercules, 2000; Hauck et al, 2001; Kálasz & Báthori, 2001; Hauck & Schulz, 2002; Wu & Chen, 2002; Crecelius, Clench, & Richards, 2003; Salo et al, 2003; Santos et al, 2004). In this approach, analytes were separated on TLC plates, which were then coated with matrix and subsequently introduced into the MALDI source.…”