Liquid chromatography—mass ionization

A liquid chromatography-mass spectrometry (LC-MS) method that can quantitatively analyze urinar y normal and modified nucleosides in less than 30 min with a good resolution and sufficient sensitivity has been developed. Nineteen kinds of normal and modified nucleosides were determined in urine samples from 10 healthy persons and 18 breast cancer patients. Compounds were separ ated on a reverse phase Kromasil C18 column (2.1 mm I.D.) by isocratic elution mode using 20 mg/1 ammonium acetate - acetonitrile (97 3 % v/v) at 200 p.l/min. A higher sensitivity was obtained in positive atmospheric pressure chemical ionization mode APCI(-i-). 

Anacleto, J. F., QuiUiam, M. A. and Boyd, R. K., Analysis of fuUerene soot extracts by liquid chromatography-mass spectrometry using atmospheric pressure ionization , in Proceedings of the 41st ASMS Conference on Mass Spectrometry and Allied Topics, San Francisco, CA, May 30-June 4, 1993, p. 1083. 

Figure 5.1 Pesticides included in the systematic investigations on APCI-MS signal response dependence on eluent flow rate the parameter IsTow represents the distribution coefficient of the pesticide between n-octanol and water. Reprinted from J. Chromatogr, A, 937, Asperger, A., Efer, 1., Koal, T. and Engewald, W., On the signal response of various pesticides in electrospray and atmospheric pressure chemical ionization depending on the flow rate of eluent applied in liquid chromatography-mass spectrometry , 65-72, Copyright (2001), with permission from Elsevier Science.

Wu, X. and Prior, R.L., Identification and characterization of anthocyanins hy high performance liquid chromatography-electrospray ionization-tandem mass spectrometry in common foods in the United States vegetables, nuts, and grains, J. Agric. Food Chem., 53, 3101, 2005. 

Stintzing, F.C., Schieber, A., and Carle, R., Identification of betalains from yellow beet (Beta vulgaris L.) and cactus pear (Opuntia ficus-indica (L.) Mill.) by high-performance liquid chromatography-electrospray ionization mass spectrometry, J. Agric. Food Chem., 50, 2302, 2002. 

Li, H. et ah. Determination of carotenoids and all-fra 5-retinol in fish eggs by liquid chromatography-electrospray ionization-tandem mass spectrometry, J. Chromatogr. B, 816, 49, 2005. 

Van Breemen, R.B. et al.. Liquid chromatography/mass spectrometry of carotenoids using atmospheric pressure chemical ionization, J. Mass Spectrom., 31, 975, 1996. Tian, Q., Duncan C.J.G., and Schwartz S. J., Atmospheric pressure chemical ionization mass spectrometry and in-source fragmentation of lutein esters, J. Mass Spectrom., 38, 990, 2003. 

Gosetti, F. et ah. Oxidative degradation of food dye El33 Brilliant Blue FCF. Liquid chromatography-electrospray ionization mass spectrometry identification of the degradation pathway, J. Chromatogr. A, 1054, 379, 2004. 

Liquid chromatography/mass spectrometry Lower limit of detection Limit of detection Limit of quantitation Florseshoe crab hemocyanin Liquid scintillation counting Matrix-assisted laser desorption/ ionization mass spectrometry m -Maleimidobenzoy 1-A -Hydroxysuccinimide 1 -Cyclohexyl-3-(2-Morptiolino-ethyl)carbodiimide rnetlio-/ -Toluenesulfonate (same as CDI)... 

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,... 

LC/MS/MS. LC/MS/MS is used for separation and quantitation of the metabolites. Using multiple reaction monitoring (MRM) in the negative ion electrospray ionization (ESI) mode, LC/MS/MS gives superior specificity and sensitivity to conventional liquid chromatography/mass spectrometry (LC/MS) techniques. The improved specificity eliminates interferences typically found in LC/MS or liquid chro-matography/ultraviolet (LC/UV) analyses. Data acquisition is accomplished with a data system that provides complete instmment control of the mass spectrometer. 

More recently, liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) have been evaluated as possible alternative methods for carfentrazone-ethyl compounds in crop matrices. The LC/MS methods allow the chemical derivatization step for the acid metabolites to be avoided, reducing the analysis time. These new methods provide excellent sensitivity and method recovery for carfentrazone-ethyl. However, the final sample extracts, after being cleaned up extensively using three SPE cartridges, still exhibited ionization suppression due to the matrix background for the acid metabolites. Acceptable method recoveries (70-120%) of carfentrazone-ethyl metabolites have not yet been obtained. 

E.M. Thurman, 1. Ferrer, and D. Barcelo, The ionization-continuum diagram a concept for selection of APCl and ESI conditions for HPLC/MS of pesticides , in 17th Montreux Symposium on Liquid Chromatography/Mass Spectrometry, Montreux, Switzerland, November 8-10, 2000 , p. 31 (2000). 

The fenoxycarb recoveries for orange, onion, grape, and tomato samples ranged from 63 to 70%. The LOQ and LOD were 0.01 mg kg and 0.005 mg kg , respectively, when using liquid chromatography/electrospray ionization mass spectrometry (LC/ESI/MS). 

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS)... 

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

S., Simultaneous determination of urinary cystathionine, lanthionine, S-(2-aminoethyl)-L-cysteine and their cyclic compounds using liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization, /. Chromatogr. B, 698, 301, 1997. 

A different strategy has been applied in our work, that emphasizes the importance of DNA stability on hole transfer within double-stranded DNA. This work is based on determination of the overall yield of oxidized nucleosides that arise from the conversion of initially generated purine and pyrimidine radical cations within DNA exposed to two-photon UVC laser pulses. On the one hand, this work benefits from the excellent current knowledge of chemical reactions involving the radical cations of DNA bases, and on the other hand, from major analytical improvements that include recent availability of the powerful technique of high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (CLHP-ESI-MS/MS) [16-18]. 

Fang, J. Barcelona, M. J. Structural determination and quantitative analysis of bacterial phospholipids using liquid chromatography electrospray ionization mass spectrometry./. Microbiol. Meth. 1998,33,23-35. 

Dunlop, K. Y. Li, L. Automated Mass Analysis of low-molecular-mass bacterial proteome by liquid chromatography-electrospray ionization mass spectrometry. J. Chromatogr. A 2001, 925,123-132. 

Chong, B.E., Yan, F., Lubman, D.M., Miller, F.R. (2001). Chromatofocusing nonporous reversed-phase high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry of proteins from human breast cancer whole cell lysates a novel two-dimensional liquid chromatography/mass spectrometry method. Rapid Com-mun. Mass Spectrom. 15, 291-296. 

Premstaller, A., Oberacher, H., Walcher, W., Timperio, A.M., Zolla, L., Chervet, J.P., Cavusoglu, N., van Dorsselaer, A., Huber, C.G. (2001). High-performance liquid chromatography-electrospray ionization mass spectrometry using monolithic capillary columns for proteomic studies. Anal. Chem. 73, 2390-2396. 

Racaityte, K., Lutz, E.S.M., Unger, K.K., Lubda, D., Boos, K.S. (2000). Analysis of neuropeptide Y and its metabolites by high-performance liquid chromatography—electrospray ionization mass spectrometry and integrated sample cleanup with a novel restricted-access sulphonic acid cation exchanger. J. Chromatogr. A 890, 135-144. 

Huber, C.G., Premstaller, A. (1999). Evaluation of volatile eluents and electrolytes for high-performance liquid chromatography-electrospray ionization mass spectrometry and capillary electrophoresis-electrospray ionization mass spectrometry of proteins. I. Liquid chromatography. J. Chromatogr. A 849, 161-173. 

Whitelegge, J.P, Zhang, H., Aguilera, R., Taylor, R.M., Cramer, W.A. (2002). Full subunit coverage liquid chromatography electrospray ionization mass spectrometry (LCMS+) of an oligomeric membrane protein cytochrome b(6)f complex from spinach and the cyanobacterium Mastigocladus laminosus. Mol. Cell. Proteomics. 1, 816-827. 

Kuehn, A.V., Neubert, R.H.H. (2004). Characterization of mixtures of alkyl polyglycosides (plantacare). by liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry. Pharm. Res. 21(12), 2347-2353. 

Zhu, J. (2004). Liquid chromatography-mass spectrometry of nonionic surfactants using electrospray ionization. J. Surfactants Detergents 7(4), 421 -23. 

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