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In this paper, an accurate and route method was developed to quantitative determine daidzein, genistein, glycitein, daidzin, glycitin, 6"-O-acetyldaidzin, 6"-O-acetylglycitin and 6"-O-acetylgenistin contents in selected high and low isoflavones in nutrition supplements by on line liquid chromatography-atmospheric pressure chemical ionisation mass spectrometry (LC-APCI-MS). Improved extraction and hydrolysis methods of the isoflavones from three nutrition supplements were also studied and a rapid extraction method was developed. Comparison of different MS2 and MS3 spectra of isoflavones and some unknown compounds were also explored and proposed pathway fragments of nine isoflavones were first systematically suggested.

Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation., (Copyright 2001 John Wiley & Sons, Ltd.)

In order to optimise the analysis of urinary nucleosides by high performance liquid chromatography/mass spectrometry (HPLC/MS), the HPLC separation of these compounds was performed at different 'flow rates' and 0.2mL/min was found to give both a better separation and ionisation. The ionisation conditions were optimised to give the best intensity of the molecules quasi-molecular ions. The ion distribution profile and ionisation in both positive and negative mode were examined and the detection of the protonated molecule in positive mode chosen for further analysis. The limits of detection of the method developed are reported and representative LC/MS and LC/MS/MS spectra shown. Typical urinary nucleoside chromatograms are presented., (Copyright 2000 John Wiley & Sons, Ltd.)

Mixtures of porphyrins derived from natural sources can be readily separated by high-pressure liquid chromatography both analytically and on a preparative scale. A variety of procedures have been developed not only for the esters but also for free acids, and on the analytical scale quantitation is easily achieved by visible absorption. The retention times are largely characteristic of the number of carboxylic acid side chains (or other polar groups) but further information can be obtained by mass spectrometric studies of the various fractions. Field desorption mass spectrometry is particularly useful for this purpose because the emitter wire can be dipped directly into the eluates. The field desorption spectra of porphyrin free acids and esters as well as their metal complexes give essentially molecular ions with little or no fragmentation in most cases, whereas electron-impact mass spectrometry, particularly of free acids, is impeded by the low volatility of porphyrins. Mixtures can also be analysed by field desorption mass spectrometry, and this provides not only a rapid qualitative assessment of the components of a mixture, but also a check on the subsequent chromatographic separations.

Combined gas chromatography mass spectrometry, because of its ability to provide both high sensitivity and specificity, has become a vital technique for the identification and quantitation of natural and synthetic chemicals in a wide variety of areas. Unfortunately, a very large number of organic compounds are not directly amenable to gas chromatography since they are thermally labile and/or of low volatility. Chemical modification of compounds of interest can assist in some cases, but it is not universally applicable. High performance liquid chromatography has been increasingly utilized for studies of compounds of these types since heat is not usually involved in the analysis. Combined liquid chromatography mass spectrometry would lend a new dimension to these studies, enabling the separating ability of the liquid chromatograph to be combined with the sensitivity and specificity of the mass spectrometer. Approaches to liquid chromatography mass spectrometry are discussed. Using examples from our liquid chromatographic mass spectrometric studies of natural compounds, drugs and pesticides, the current abilities of such systems to identify and quantify natural and synthetic chemicals present in a complex matrix of other chemicals are described.