Liquid chromatography mass spectrometry efficiency

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. 

Li H.Q., F. Jiku, and H.F. Schroder. 2000. Assessment of the pollutant elimination efficiency by gas chromatography/mass spectrometry, liquid chromatography-mass spectrometry and—tandem mass spectrometry comparison of conventional and membrane-assisted biological wastewater treatment processes. J. Chromatogr. A 889 155-176. 

Dear GJ, Plumb RS, Sweatman BC et al. (2000) Mass directed peak selection, an efficient method of drug metabolite identification using directly coupled liquid chromatography-mass spectrometry-nuclear magnetic resonance spectroscopy. J Chromatogr B Biomed Sci Appl 748 281-293... 

A method that uses high performance liquid chromatography/ mass spectrometry (HPLC/MS) for the analysis of chlorinated phenoxyacid herbicides is described. During method development different techniques were used to increase both the sensitivity and the specificity of thermospray HPLC/MS for chlorinated acid herbicides. These included the operation of the instrument in the negative chemical ionization (NCI) mode initiated by discharge and the use of a wire-repeller in the ion source for efficient extraction of positive ions. Single quadrupole repeller-induced and multiple quadrupole collision activated dissociation (CAD) experiments were also performed to increase the structural information of the mass spectra. 

MINIATURIZED FORMATS FOR EFFICIENT LIQUID CHROMATOGRAPHY MASS SPECTROMETRY-BASED PROTEOMICS AND THERAPEUTIC DEVELOPMENT... 

Idborg, H. Edlund, P.O. Jacobsson, S.P. Multivariate Approaches for Efficient Detection of Potential Metabolites from Liquid Chromatography/Mass Spectrometry Data, Rapid Commun. Mass Spectrom. 18(9), 944-954 (2004). 

The ability to gather more knowledge faster with smaller quantities of complex samples can support these increased demands on pharmaceutical R D. The advanced approaches and technologies associated with liquid chromatography-mass spectrometry (LC-MS) continue to play a significant role within drug discovery because of the inherent sensitivity and selectivity of this analytical platform. Improvements with increased throughput and easier-to-use instruments have allowed researchers unprecedented levels of efficiency and productivity. 

It has been coupled with enzyme immunoassay for efficient and fast polyaromatic hydrocarbon (PAH) screening in soil [21]. In a number of studies both static and dynamic superheated water extraction has been coupled to solid-phase microextraction [15, 25, 28, 30, 35, 38], sometimes with other analytical methods also coupled. It has been coupled with gas chromatography-mass spectrometry [31], capillary electrophoresis [31], liquid chromatography-mass spectrometry [32] and liquid chromatography-gas chromatography [41]. Sometimes other chemicals are added to the water used, such as acid [42] or phosphate buffer [43]. Different trapping methods for analytical extraction have been examined [44]. 

Thermo Scientific has introduced the 2D (or linear) liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/ MS/MS) ion trap mass spectrometer [11], known as the LTQ. The ion injection efficiency has been improved dramatically in the linear ion trap. In addition, ions in a linear ion trap are distributed along the central axis, rather than concentrated in the ion trap center for a 3D ion trap thus, both charge capacity and sensitivity in a linear ion trap have been increased significantly. Although at the present time there is neither commercial linear ion trap/GC/MS nor commercial linear ion trap/GC/ MS/MS instruments, a commercial version of a linear ion trap/GC/MS is expected to appear in the near future. 

Idborg H, et al. Multivariate approaches for efficient detection of potential metabolites from liquid chromatography/mass spectrometry data. Rapid Commun Mass Spectrom 2004 18 944-954. 

Dear, G.J. Ayrton, J. Plumb, R. Sweatman, B.C. Ismail, I. M. Fraser, I.J. Mutch, P.J. A rapid and efficient approach to metahohte identification using nuclear magnetic resonance spectroscopy, liquid chromatography/mass spectrometry and hquid chromatography/nuclear magnetic resonance spectroscopy/sequential mass spectrometry. Rapid Commun. Mass Spectrom. 1998,12, 2023-2030. 

Stage that requires high efficiency as well as speed, due to the complexity of the sample matrix, and hence it is particularly challenging to achieve the goals. Therefore, the development of a rapid, sensitive, and reproducible method has been required for separation and determination of capsaicinoid compounds. The addition of ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) method fulfilled these aforementioned demands and showed some complementary advantages to the conventional HPLC-MS, u-HPLC methods in terms of shorter analysis times, low sample volume, and much improved sensitivity [71]. Therefore, nowadays this UPLC-MS technique is routinely performed in pharmaceutical industries and related contract research institutes, laboratories concerned with biochemistry, biotechnology, environmental analysis, natural product research, and several other research fields. The UPLC-MS method has successfully been applied for the determination of n-DHC, C, DHC, h-C, and h-DHC present in the varieties of hot peppers [71]. 

During the last decade, the use of liquid chromatography-mass spectrometry (LC-MS) technology has been increasing in clinical and forensic laboratories. This expansion is in part because of the gradual introduction of relatively low-cost LC-MS instruments and the availability of robust atmospheric pressure ionization (API) sources. The combination of liquid chromatographic separation and mass spectrometric detection provides the laboratory an efficient... 

Efficient purification performed by high-performance liquid chromatography (HPLC) and high-sensitivity gas chromatography-mass spectrometry (GC-MS) using a capillary column dramatically improved the purification and identification procedure for GAs as in other natural products. The improved sensitivity in instrumental analyses also requires a correspondingly smaller quantity of GAs for characterization. The purification procedure for GAs has become simpler than that in earlier decades. 

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