Liquid chromatography-mass moving belt interface

All gas chromotography/mass spectrometry (GC/MS) analyses of monomers and intermediates were performed on a Finnigan 1020 GC/MS using a 30-m RSL-150 fused silica capillary column. Liquid chromatography/mass spectrometry (LC/NS) was performed on a Finnigan 4500 mass spectrometer using acetonitrile-water eluent and a moving belt LC/MS interface. 

D.E. Games, P. Hirter, W. Kuhnz, E. Lewis, N.C.A. Weerasinghe and S.A. Westwood, Studies of combined liquid chromatography-mass spectrometry with a moving-belt interface, J. Chromatogr., 203 (1981) 131-138. 

Coupling of liquid chromatography to mass spectrometry has not only led to a wide variety of interfaces, but also initiated the development of new ionization methods. [8-13,62] In retrospect, the moving belt interface seems rather a curiosity than a LC-interface. The LC effluent is deposited onto a metal wire or belt which is heated thereafter to desolvate the sample. Then, the belt traverses a region of... 

Games, D. E. McDowell, M. A. Levsen, K. Schafer, K. H. Dobberstein, P. Gower, J. L. 1984. A comparison of moving belt interfaces for liquid chromatography mass spectrometry. Biomed. Mass Spectrom., 11, 87-95. 

Over 30 years of liquid chromatography-mass spectrometry (LC-MS) research has resulted in a considerable number of different interfaces (Ch. 3.2). A variety of LC-MS interfaces have been proposed and built in the various research laboratories, and some of them have been adapted by instmment manufacturers and became commercially available. With the advent in the early 1990 s of interfaces based on atmospheric-pressure ionization (API), most of these interfaces have become obsolete. However, in order to appreciate LC-MS, one carmot simply ignore these earlier developments. This chapter is devoted to the older LC-MS interfaces, which is certainly important in understanding the histoiy and development of LC-MS. Attention is paid to principles, instrumentation, and application of the capillary inlet, pneumatic vacuum nebulizers, the moving-belt interface, direct liquid introduction, continuous-flow fast-atom bombardment interfaces, thermospray, and the particle-beam interface. More elaborate discussions on these interfaces can be found in previous editions of this book. 

Combined liquid chromatography/mass spectrometry (LC/MS)can play an important role in both qualitative and quantitative bioanalysis. LC/MS can be performed with a number of interfaces. Three interfaces are presently available in our laboratories i.e., the thermospray interface (TSP), the moving-belt interface (MBI), and continuous-flow fast atom bombardment (CF-FAB). These interfaces are supplementary with respect to their applicability and the type of information that can be obtained. 

P. Arpino, Combined liquid chromatography mass spectrometry I Coupling by means of a moving belt interface. Mass Spectrom. Rev. 8, 35-55 (1989). 

M. J. Hayes, E. P. Lankmayer, P. Vouros, and B. L. Karger, Moving belt interface with spray deposition for liquid chromatography/mass spectrometry. Anal Chem. 55, 1745-1752 (1983). 

Jungalwala, F. B., Evans, J. E., Kadowaki, H. and McCluer, R. H. (1984) High performance liquid chromatography-chemical ionisation mass spectrometry of sphingoid bases using moving-belt interface. J. Lipid Res., 25, 209-16. 

Games, D. E., 1981, Combined liquid chromatography-mass spectrometry with a moving-belt interface, in Soft Ionisation Biological Mass Spectrometry (H. R. Morris, ed.), pp. 54-68, Heyden and Son, London. 

Games, D.E. Hirter, P. Kuhnz, W. Lewis, E. Weerasinghe, N.C.A. West-wood, S.A. Studies of Combined Liquid Chromatography-Mass Spectrometry With a Moving-Belt Interface. J. Chromatogr. 1981,203, 131-138. 

The mass spectrometer is a very sensitive and selective instrument. However, the introduction of the eluent into the vacuum chamber and the resulting significant pressure drop reduces the sensitivity. The gas exhaust power of a normal vacuum pump is some 10 ml min-1 so high capacity or turbo vacuum pumps are usually needed. The gas-phase volume corresponding to 1 ml of liquid is 176 ml for -hexane, 384 ml for ethanol, 429 ml for acetonitrile, 554 ml for methanol, and 1245 ml for water under standard conditions (0°C, 1 atmosphere). The elimination of the mobile phase solvent is therefore important, otherwise the expanding eluent will destroy the vacuum in the detector. Several methods to accomplish this have been developed. The commercialized interfaces are thermo-spray, moving-belt, electrospray ionization, ion-spray, and atmospheric pressure ionization. The influence of the eluent is very complex, and the modification of eluent components and the selection of an interface are therefore important. Micro-liquid chromatography is suitable for this detector, due to its very small flow rate (usually only 10 p min - ). 

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