Chromatography-coupled mass spectrometry

Reaction scheme of a ruthenium benzylidene complex showing the formation of a reactive intermediate (compound 2) and final product (compound 3), along with the mass spectrum obtained after isolation of compound 2 and subsequent reaction with 1-butene. Adapted with permission from [12]. Copyright 1998 John Wiley Sons. 

GC-MS spectrum showing the presence of l,5-diaza-2,4,6,8-tetrasila-[3,3,0]-bicyclooctane. 

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Several papers utilizing 3 mm probe capabilities were also published that delved into the area of protein structures. Hepatocyte nuclear factor 4 was studied by a group lead by Williams.155 It is interesting to note that a 2.7 A X-ray study showed a fatty acid in the pocket of HNF4y. Gas chromatography coupled mass spectrometry (GC/MS) and 3 mm NMR studies of extracts from purified HNF4x led to the identification of mixtures of saturated and crs-monounsaturated Ci4 to Qg fatty acids. Bertini and co-workers156 utilized 3 mm probe capabilities in the determination of the solution structure of CopC, a cupredoxin-like protein involved in copper homeostasis. 

The on-line principle has also been extended into the field of detection (Fig. 8). Thus, it is now possible to record FTIR [27-31] and Raman spectra in situ [32, 33], and there have been considerable advances in the on-line coupling of thin-layer chromatography with mass spectrometry. Here it has been, above all, the research groups of Wilson [34-36] and Busch [37-40] that have made the necessary instrumental and methodological advances, so that TLC must no longer be viewed as merely a clean-up method. Rather it forms the essential central point for all these on-line coupling techniques. 

Huang M.Q. et al., 2006. Increased productivity in quantitative bioanalysis using a monohth column coupled with high-flow direct-injection hquid chromatography/tandem mass spectrometry. Rapid Commun Mass Spectrom 20 1709. 

J. Abian. The Coupling of Gas and Liquid Chromatography with Mass Spectrometry. J. Mass Spectrom., 34(1999) 157-168. 

Moder M, Popp P, Eisert R, Pawliszyn J. Determination of polar pesticides in soil by solid phase microextraction coupled to high-performance liquid chromatography-electrospray/mass spectrometry. Fresenius. J. Anal. Chem. 1999 363 680-685. 

G.J. Van Berkel, M.J. Ford and M.A. Deibel, Thin-layer chromatography and mass spectrometry coupled using desorption electrospray ionization. Anal. Chem., 11 (2005)1207-1215. 

Coupling of liquid chromatography to mass spectrometry has not only led to a wide variety of interfaces, but also initiated the development of new ionization methods. [8-13,62] In retrospect, the moving belt interface seems rather a curiosity than a LC-interface. The LC effluent is deposited onto a metal wire or belt which is heated thereafter to desolvate the sample. Then, the belt traverses a region of... 

Xia, Y.-Q., Bakhtiar, R., and Erankhn, R.B., Automated online dual-column extraction coupled with teicoplanin stationary phase for simultaneous determination of (R)- and (5)-propranolol in rat plasma using liquid chromatography-tandem mass spectrometry, J. Chromatogr. B, 788, 317, 2003. 

Petersson, P., Jornten-Karlsson, M., and Stalebro, M. (2003). Direct coupling of micellar electrokinetic chromatography to mass spectrometry using a volatile buffer system based on perfluorooctanoic acid and ammonia. Electrophoresis 24, 999—1007. 

While the first coupling of gas chromatography and mass spectrometry had been reported in the late fifties [4] one had to wait for almost another 20 years before the direct interfacing of liquid chromatography with mass spectrometry (LC-MS) was described by Arpino et al. [5]. With the direct liquid interface (DLI) the effluent of the chromatographic column was directly introduced in the electron impact source. Contrarily to gas chromatography coupled to mass spectrometry (GC-MS), LC-MS did do not catch on as rapidly. One of the reasons was that the MS interface could only handle LC fiow rates of a few microliters per minute. Another limitation was that electron impact or chemical ionization was not suit-... 

In atmospheric pressure ionization sources (API) the ions are first formed at atmospheric pressure and then transferred into the vacuum. In addition, some API sources are capable of ionizing neutral molecules in solution or in the gas phase prior to ion transfer to the mass spectrometer. Because no liquid is introduced into the mass spectrometer these sources are particularly attractive for the coupling of liquid chromatography with mass spectrometry. Pneumatically assisted electrospray (ESI), atmospheric pressure chemical ionization (APCI) or atmospheric pressure photoionization (APPI) are the most widely used techniques. 

Isotope Abundances Negative Ions Synthetic Models V. High-Resolution Studies VI. Metastable-Ion Techniques VII. Coupled Gas Chromatography and Mass Spectrometry Inorganic and Organometallic Compounds VIII. Conclusion. ... 

VII. Coupled Gas Chromatography and Mass Spectrometry Applied to Inorganic and Organometallic Compounds... 

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