Chromatography and identification

Identification of decomposition products and metabolic products is most conveniently done by their isolation using thin layer chromatography and identification by use of field desorption mass spectrometry. 

Ghassempour, A. et al. Monitoring of N-nitrosodiethanolamine in cosmetic products by ion-pair complex liquid chromatography and identification with negative ion electrospray ionization mass spectrometry. J. Chromatogr. A. 2008, 1185,43-48. 

Chromatography and Identification of Metabolic Products. Each culture broth (12 liters) was extracted with ether (3 liters x 4) and the extract was dried over anhydrous sodium sulfate. The ether extract was analyzed by gas liquid chromatography (GLC) Shimadzu GC-4C equipped with a stainless steel column (3 m x 3 mm i.d.) packed with 10% PEG-20M on 80 -100 mesh of Celite 545. 

Oil of Hops. Volatile oil from strobiles of Hamulus lupulus L, Moraceae. Conslit. 65-70% humulene, ter -penes. Gas chromatography and identification of constituents Buttery er ah. Nature 280, 435 (1963). See also review by Stevens, Chem. Rev. 67, 19 (1967). 

A. P. Wall, Resolution of synthetic (+)- and (-)-epibatidine by chiral high performance liquid chromatography and identification of the natural isomer, J. Liq. Chromatogr., 17(1994)1257. 

Fales, H.M. PanneU, L.K. Sokoloski, E.A. Carmeci, P. Separation of methyl violet 2B hy high-speed countercurrent chromatography and identification hy Califomium-252 plasma desorption mass spectrometry. Anal. Chem. 1985, 57, 376-378. 

Buschmann, N., Merschel, L., and Wodarczak, S. (1996). Analytical methods for alkyl polyglucosides. Part II. Qualitative determination using thin layer chromatography and identification by means of in-situ secondary ion mass spectrometry. Tenside, Surfactants, Deterg. 33 16-20. 

One example of the ability of this combined technique to analyze complex mixtures is provided by the use of GC-MS for a sample of mineral oil with over 50 components. Accurate identification of peaks from amounts of solutes ranging from 5 ng to 200 ng was possible. The pyrolysis of polymers, followed by separation by gas chromatography and identification by mass spectrometry (Py-GC-MS) extends the combination to include three distinct techniques. 

Analysis. Dilute aqueous solutions of hydroxyhydroquiaone turn blue-green temporarily when mixed with ferric chloride. The solutions darken upon addition of small amounts, and turn red with additions of larger amounts of sodium carbonate. Derivatives used for identification are the picrate, which forms orange-red needles (mp of 96°C), and the triacetate (mp 96—97°C). Thin-layer chromatography and Hquid chromatography are well suited for the quahtative and quantitative estimation of hydroxyhydroquiaone (93,94). 

There are many reports of the use of mass spectroscopy coupled to chromatography outlets for detection and identification of dmgs and metabolites. An example is compound 126 (99MI2, 99MI3). Carboxylic acids have been converted into hydrazides and hence into 3-substituted [l,2,4]triazolo... 

The need for a more definitive identification of HPLC eluates than that provided by retention times alone has been discussed previously, as have the incompatibilities between the operating characteristics of liquid chromatography and mass spectrometry. The combination of the two techniques was originally achieved by the physical isolation of fractions as they eluted from an HPLC column, followed by the removal of the mobile phase, usually by evaporation, and transfer of the analyte(s) into the mass spectrometer by using an appropriate probe. 

Marutoiu C, Sarbu C, Vlassa M, et al. 1986. A new separation and identification method of some organophosphorus pesticide by means of temperature programming gradient thin-layer chromatography. Analysis 14 95-98. 

Ramsey JD, Flanagan RJ. 1982. Detection and identification of volatile organic compounds in blood by headspace gas chromatography as an aide to the diagnosis of solvent abuse. J Chromatogr 240 423-444. 

ZEEB D J, NELSON B c, ALBERT K and DALLUGE J J (2000) Separation and identification of twelve catechins in tea using liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry , Chem, 72, 5020-26. 

Khachik, F. and Beecher, G.R., Separation and identification of carotenoids and carotenol fatty acid esters in some squash products by liquid chromatography. 1. Quantification of carotenoids and related esters by HPLC, J. Agric. Food Chem., 36, 929, 1988. 

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