HPLC-particle beam mass spectrometry

Cappiello s research group applied micro-HPLC to the screening of water samples for pesticide contamination. With electron ionization mass spectrometric detection and the use of two microcolumns packed with a Cig silica-based stationary phase, they performed the preconcentration of water samples and successfully detected trace levels of pollutants in similar samples. They also showed that ion-interaction micro-HPLC on a Cig stationary phase with hexylamine as the ion-pair reagent and coupling to particle beam mass spectrometry could be successfully used for the analysis of herbicides ranging from acidic species such as... 

The availability of commercial bench-top mass spectrometry detectors for HPLC is facilitating the development of HPLC-MS methods for many analytes. This is more common in pharmaceutical than food applications. As is generally the case, mass spectrometry is first being applied to standard solutions and relatively simple samples before being applied to more complex food matrices. A standard mixture of ten vitamers, AA, DHAA, PN, PL, PM, thiamine, nicotinic acid, nicotinamide, pantothenic acid and biotin, were recently determined by HPLC-particle beam... 

The first approaches to the coupling of liquid-phase separation techniques with mass spectrometry were designed for HPLC needs, starting in the 1970s with since-forgotten techniques such as direct liquid introduction (DLI) and moving belt. In the 1980s, techniques such as thermospray, continuous-flow-fast atom bombardment (CF-FAB), and particle beam arose. 

The use of liquid chromatography-mass spectrometry (LC-MS) is becoming more popular because of the increasing number of LC-MS interfaces commercially available thermospray (TSP), particle beam (PB), and atmospheric pressure ionization (API). Coupled with mass spectroscopy, HPLC provides the analyst with a powerful tool for residue determination. 

In thermospray interfaces, the column effluent is rapidly heated in a narrow bore capillary to allow partial evaporation of the solvent. Ionisation occurs by ion-evaporation or solvent-mediated chemical ionisation initiated by electrons from a heated filament or discharge electrode. In the particle beam interface the column effluent is pneumatically nebulised in an atmospheric pressure desolvation chamber this is connected to a momentum separator where the analyte is transferred to the MS ion source and solvent molecules are pumped away. Magi and Ianni (1998) used LC-MS with a particle beam interface for the determination of tributyl tin in the marine environment. Florencio et al. (1997) compared a wide range of mass spectrometry techniques including ICP-MS for the identification of arsenic species in estuarine waters. Applications of HPLC-MS for speciation studies are given in Table 4.3. 

RB van Breemen, D Nikolic, X Xu, Y Xiong, M van Lieshout, CE West, AB Schilling. Development of a method for quantitation of retinol and retinyl palmitate in human serum using high performance liquid chromatography-ahnospheric pressure chemical ionization mass spectrometry. J Chromatogr A 794 245-251, 1998. R Andreoli, M Careri, P Manini, G Mori, M Musci. HPLC analysis of fat-soluble vitamins on standard and narrow-bore columns with UV, electrochemical and particle beam MS detection Chromatographia 44 605-612, 1997. 

Contrary to the predictions in 1989 (27), LC-MS has not experienced a breakthrough as an analytical technique in the vitamin E area. One research group reported two studies on the determination of liposoluble vitamins in foods and infant formulas by LC-particle beam MS (44,50). Caimi and Brenna coupled HPLC with combustion isotope ratio mass spectrometry for the analysis of mixtures of liposoluble vitamins, including a- and y-tocopherol (171). 

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