Chromatography with mass spectrometry

Diethyl sulphate and dimethyl sulphate Lab method using Tenax sorbent tube, thermal desorption and gas chromatography with mass spectrometry 89... 

What are the Advantages of Linking High Performance Liquid Chromatography with Mass Spectrometry ... 

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. 

Schroder, H.E (2003). Determination of fluorinated surfactants and their metabolites in sewage sludge samples by liquid chromatography with mass spectrometry and tandem mass spectrometry after pressurized liquid extraction and separation on fluorine-modified reversed-phase sorbents. J. Chromatogr. A 1020(1), 131-151. 

M. R. Guasch Jane, M. Ibem Gomez, C. Andres Lacueva, O. Jauregui and R. M. Lamuela Raventos, Liquid chromatography with mass spectrometry in tandem mode applied for the identification of wine markers in residues from ancient Egyptian vessels, Analytical Chemistry, 76, 1672 1677 (2004). 

Fig. 19.10. Combining liquid chromatography with mass spectrometry involves a difficult courtship [38],...

R.C. Willoughby and R.F. Browner, Monodisperse aerosol generation interface for combining liquid chromatography with mass spectrometry, Anal. Chem., 56 (1984) 2625-2631. 

Test methods that analyze individual compounds (e.g., benzene-toluene-ethylbenzene-xylene mixtures and PAHs) are generally applied to detect the presence of an additive or to provide concentration data needed to estimate environmental and health risks that are associated with individual compounds. Common constituent measurement techniques include gas chromatography with second-column confirmation, gas chromatography with multiple selective detectors, and gas chromatography with mass spectrometry detection (GC/MS) (EPA 8240). 

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

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. 

Tiller, P. R. Romanyshyn, L. A. Implications of matrix effects in ultrafast gradient or fast isocratic liquid chromatography with mass spectrometry in drug discovery. Rapid Commun Mass Spectrom 2002, 16, 92-98. 

Baracco, A. et al., A comparison of the combination of fast-atom bombardment with tandem mass spectrometry and of gas chromatography with mass spectrometry in the analysis of a mixture of kaempferol, kaempferide, luteolin and oleouropein, Rapid Gommun. Mass Spectrom., 9, 427,... 

Coupling of liquid chromatography with mass spectrometry provides further unequivocal online spectrometric identification of individual analytes at the very low residue levels required by regulatory agencies for confirmatory analysis... 

Coupling of liquid chromatography with mass spectrometry allows unequivocal online spectrometric identification of all nitrofurans at the very low residue concentrations required by regulatory agencies for confirmatory analysis in animal-derived foods. Typical examples of mass spectrometry applications in confirming nitrofuran residues in edible animal products employ thermospray (174, 176), ionspray (166), or atmospheric pressure chemical ionization (157) interfaces. 

Excellent separation of sulfonamides can be achieved on conventional or fused silica capillary columns, the preferred type been the DB-5 capillary column. Following separation, electron-capture detector (254, 271) can be used for the determination of these drugs with good sensitivity and specificity. To confirm the presence of sulfonamides residues in edible animal products, mass spectrometric detectors are also frequently employed. Typical examples of such applications are those coupling gas chromatography with mass spectrometry via a chemical ionization (224, 254, 271) or electron impact (223, 256, 261) interface. 

Coupling of liquid chromatography with mass spectrometry can provide unequivocal on-line spectrometric identification of anthelminthic residues in animal-derived foods. Typical applications of such techniques include the confirmation of moxidectin residues in cattle fat by liquid chromatography-thermospray mass spectrometry (352), and the confirmation of eprinomectin residues in bovine liver tissue by liquid chromatography, electrospray ionization, and multiple reaction monitoring in the MS-MS mode with positive ion detection (370). 

The number of detectors that are sensitive and selective enough to be applied online with LC is limited because the solvents used are not compatible, as in the case of immunochemical detection after reversed- or normal-phase LC. The technology of coupling is still under development and not yet available in a large number of laboratories not specialized in techniques such as LC-MS. Therefore, LC separations are frequently followed by offline detection. Confirmatory analysis of suspected liquid chromatographic peaks can be made possible by coupling liquid chromatography with mass spectrometry. Atmospheric-pressure chemical ionization LC-MS has been employed for the identification of six steroid hormones in bovine tissues (448). 

Despite its inherent analytical difficulties, gas chromatography on capillary columns in combination with sensitive and specific mass spectrometry has been widely used for separation of these analytes. Typical examples of such applications are those interfacing gas chromatography with mass spectrometry via electron impact (470, 484, 480, 489), chemical ionization (481, 478, 483, 473), or both interfaces (474, 475, 487, 488). Apart from mass spectrometry, Fourier transform infrared spectrometry has also been suggested as an alternative very useful identification tool in the area of the -agonist analysis. Capillary gas chromatography with Fourier transform infrared spectrometry was successfully employed to monitor clenbuterol, mabuterol, and salbutamol residues in bovine liver and urine (471). 

B. Ardrey, Liquid Chromatography-Mass Spectrometry An Introduction (Chichester, UK Wiley, 2003) W. M. A. Niessen. Liquid Chromatography-Mass Spectrometry, 2nd ed (New York Marcel Dekker, 1999) M. S. Lee, LC/MS Applications in Drug Development (New York Wiley, 2002) J. Abian, Historical Feature The Coupling of Gas and Liquid Chromatography with Mass Spectrometry, J. Mass Spectrom. 1999, 34, 157. 

The majority of the many methods used to study the composition of equilibrium solutions of carbohydrates examine the mixture without separating the individual components. With the discovery that the anomeric forms of sugars could be readily separated by gas chromatography of their tri-methylsilyl ethers, a new approach to the problem was found. A protocol was developed for the direct gas chromatographic analysis of the amount of each anomer present in an aqueous solution. The protocol can be used on the micro scale and can be used in enzyme assays such as that for mutarotase. The method has been made more effective by combining gas chromatography with mass spectrometry. It is shown how mass spectral intensity ratios can be used to discriminate anomers one from another. The application of these methods to the study of complex mutarotations is discussed. 

Vlase, L., Imre, S., Muntean, D., and Leucuta, S. E. (2007). Determination of loratadine and its active metabolite in human plasma by high-performance liquid chromatography with mass spectrometry detection. J. Pharm. Biomed. Anal. 44 652-657. 

---