Liquid chromatography-mass interfaces

The ion spray liquid chromatography/mass spectrometry (LC-MS) interface coupled via a postsuppressor split with an ion chromatography (IC) has been used in the analysis of alcohol sulfates. The IC-MS readily produces the molecular weight while the tandem mass spectrometric detection IC-MS-MS provides structural information [305]. 

The characteristics of an ideal liquid chromatography-mass spectrometry interface have been discussed, with emphasis having been placed upon the major incompatibilities of the two component techniques that need to be overcome to allow the combination to function effectively. 

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

Sakairi, M. and Kato, Y., Multi-atmospheric pressure ionization interface for liquid chromatography-mass spectrometry, ]. Chromatogr. A. 794, 391, 1998. 

Simpson, R. C. Fenselau, C. Hardy, M. R. Townsend, R. R. Lee, Y. C. Cotter, R. J. Adaptation of a thermospray liquid chromatography/mass spectrometry interface for use with alkaline exchange liquid chromatography of carbohydrates. Anal. Chem. 1990, 62, 248-252. 

The introduction and eventual commercialization of matrix-assisted laser desorption/ionization (MALDI) and electrospray (ESI) allowed biomarker status to be extended to proteins in 1996.15"17 With a few exceptions, ESI has been used in conjunction with extractions and high-pressure liquid chromatography (UPLC) interfaced with mass spectrometry. MALDI, on the other hand, has been widely adapted for rapid analysis of intact organisms, supported by bioinformatics.1819... 

Blakley C.R. and Vestal M.L., 1983. Themospray interface for liquid chromatography/mass spectrometry. Anal Chem 55 750. 

C. R. Blakley and M. L. Vestal. Thermospray Interface for Liquid Chromatography/Mass Spectrometry. Anal Chem., 55(1983) 750-754. 

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. 

M.A. Baldwin and F.W. McLafferty, Liquid chromatography-mass spectrometry interface. I The direct introduction of liquid solutions into a chemical ionization mass spectrometer, Org. Mass Spectrom., 7 (1973) 1111-1112. 

R.P.W. Scott, C.G. Scott, M. Munroe and J. Hess Jr., Interface for on-line liquid chromatography-mass spectroscopy analysis, J. Chromatogr., 99 (1974) 395-405. 

Based on a new technology, particle beam enhanced liquid chromatography-mass spectrometry expands a chemist s ability to analyse a vast variety of substances. Electron impact spectra from the system are reproducible and can be searched against standard or custom libraries for positive compound identification. Chemical ionization spectra can also be produced. Simplicity is a key feature. A simple adjustment to the particle beam interface is all it takes. 

Puig et al. [450] determined ng/1 levels of priority methyl-, nitro-, and chloro-phenols in river water samples by an automated on-line SPE technique, followed by liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionization (APCI) and ion spray interfaces. 

Winkler, P.C. Perkins, D.D. Williams, D.K. Browner, R.F. Performance of an Improved Monodisperse Aerosol Generation Interface for Liquid Chromatography/Mass Spectrometry. Anal. Chem. 1988,60,489-493. 

Millington, D.S. Yorke, D.A. Bums, P. A New Liquid Chromatography-Mass Spectrometry Interface. Adv. Mass Spectrom. 1980, SB, 1819-1825. 

TFA is advantageous in that it enhances the peak shape and efficiency for some polar compounds and its higher volatility is more desirable in liquid chromatography-mass spectrometry (LC-MS) operative conditions. The interfacing of LC methodologies with MS is discussed later in Section 2.3.1.4. 

With the work of Fenn and co-workers, liquid chromatography—electrospray interfaces for mass spectrometers were developed in 1984. Subsequently, the Pacific Northwest Laboratory began work in the area of CE—ESI—MS under the direction of Richard Smith and published the initial paper describing on-line CE—MS in 1987. Initial interface designs involved removing the polyimide at the end of the capillary in favor of a layer of silver for electrical contact. This interface was limited due to below optimum flow rates and limited lifetime of the metallized capillary. The introduction of the sheath flow design dramatically improved the CE—MS results. In lieu of being connected to a standard outlet buffer, the CE—MS interface used the outlet end of electrophoretic capillary connected directly to the electrospray mass spectrometer. 

Which liquid chromatography-mass spectrometry interface, atmospheric pressure chemical ionization or electrospray, requires analyte ions to be in solution prior to the interface How does the other interface create gaseous ions from neutral species in solution ... 

The use of liquid chromatography-mass spectrometry (LC-MS) is becoming more popular because of the increasing number of LC-MS interfaces commercially available thermospray (TSP), particle beam (PB), and atmospheric pressure ionization (API). Coupled with mass spectroscopy, HPLC provides the analyst with a powerful tool for residue determination. 

Bruins, A. P. (1991). Liquid chromatography-mass spectrometry with ionspray and electrospray interfaces in pharmaceutical and biomedical research. J. Chromatogr. 554 39-46. 

LC/MS (Liquid Chromatography/Mass Spectrometry)—Chromatography system in which an HPLC is married to a mass spectrometric detector through an evaporated, ionizing interface. A variety of mass spectrometers are used to produce various LC/MS and LC/MS/MS configurations. MS detectors are universal, mass detectors that provide molecular weight information and can give a definitive identification of separated compounds. 

To establish a sensitive and specific liquid chromatography-mass spectrometry (time-of-flight) [LC-MS (TOF)] method for the determination of donepezil in human plasma after an oral administration of 5 mg donepezil hydrochloride tablet [29]. Alkalized plasma was extracted with isopropa-nol-n-hexane (3 97) and loratadine was used as internal standard (IS). Solutes were separated on a Cis column with a mobile phase of metha-nokacetate buffer (pH 4.0) (80 20). Detection was performed on a TOF mass spectrometry equipped with an electrospray ionization interface and operated in positive-ionization mode. Donepezil quantitation was realized by computing the peak area ratio (donepezil-loratadine) (donepezil m/z 380 [M + H]+ and loratadine m/z 383[M + H]+) and comparing them with calibration curve (r = 0.9998). The linear calibration curve was obtained in the concentration range of 0.1-15 jUg/1. The detection limit of donepezil was 0.1 /zg/1. The average recovery was more than 90%. The intra- and inter-run precision was measured to be below 15% of RSD... 

A. High-performance liquid chromatography-mass spectrometry Weidolf and Covey [121] described the application of the ionspray interface for liquid chromatography and atmospheric-pressure ionization mass spectrometry to samples obtained in a study on the metabolism of... 

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