High performance liquid chromatography electrospray interface

Reversed-phase Cig chromatography column. Keystone Scientific Betasil, 100 x 2.0-mm i.d., 5-pm particle size, 100 A, Part No. 105-701-2-CPF TSQ 7000 LC/MS/MS system with electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) interface and gradient high-performance liquid chromatography (HPLC) unit, or equivalent Vacuum manifold for use with SPE cartridges (Varian Vac Elut 10 or equivalent)... 

Liu, C. L. and Verma, S. S., Direct coupling of ionic high performance liquid chromatography with electrospray ionization mass spectrometry utilizing a microdialysis junction interface, ]. Chromatogr. A, 835, 93, 1999. 

Raynor, M.W., Dawson, G.D., Balcerzak, M., Pretorius, W.G. and Ebdon, L. (1997) Electrospray nebulisation interface for micro-high performance liquid chromatography inductively coupled plasma mass spectrometry. J. Anal. At. Spectrom., 12, 1057-1064. 

Mass spectrometry (MS) is one of the most powerful detection techniques used in liquid-phase analyses,1 mainly due to the ease of interfacing with separation techniques such as capillary electrophoresis (CE)2,3 and high-performance liquid chromatography (HPLC).4 Due to its sensitivity and applicability to a wide variety of chemical and biochemical species, MS is also used for the analysis of (bio)chemical molecules processed in microfluidics devices.5,6 Electrospray ionization (ESI)7 10 is often used to transfer samples from microfluidics chips to a mass spectrometer, involving analyte ionization directly from solutions and operating at flow rates typically used in microfluidics devices.11 Due to its effectiveness, the use of chip-MS coupling has rapidly spread in many research areas with bioanalytical applications,12 such as the... 

In one approach, the microchip interface was constmcted from modified 1/16-inch high-performance liquid chromatography (HPLC) fittings [30]. It incorporates a freestanding liquid junction formed via continuous delivery of a flow of suitable solvent which carries the separation effluent through a pneumatically assisted electrospray needle located in front of the MS orifice. In some cases, stmctural features of microchips can be utilized as parts of the ion source (e.g., ESI emitter). Thus, the resulting coupled microchip-MS systems are more compact, and the delay time between the on-chip incubation and MS detection can be decreased. For example, a capillary nanoESI emitter was successfully incorporated into a microchip CE channel for on-line CE-MS analysis [31]. Such microchip-MS systems do not require the use of external pumps because analytes can be driven toward the ion source (ESI or nanoESI) by means of electroosmosis and electrophoresis [32]. 

To do away with the problran of dealing with a complex, it is often necessary to purify the protein before subjecting it to mass spectrometry. Two dimensional gel electrophoresis and high performance liquid chromatography are the two methods that are generally applied for such purification. The peptide mixture that results from protease action is fractionated by the above named methods of purification and the eluent from these methods is directly introduced into the mass spectrometer. Here either electrospray or MALDI is used for ionization of the peptides. Thus interface between HPLC and mass spectrometry is mostly... 

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