Liquid chromatography particle beam ionization

See footnote cto Table3 LC/PB/MS = hquid chromatography/particle beam mass spectrometry LC/APcl/ESl-MS/MS = liquid chromtography/atmospheric pressure chemical ionization/electrospray ionization tandem mass spectrometry LC/FTIR = Fourier transform infrared LC/TSP-MS/MS = liquid chromatography/thermospray tandem mass spectrometry LC/TSP-MS = liquid chromatography/thermospray mass spectrometry. 

Based on a new technology, particle beam enhanced liquid chromatography-mass spectrometry expands a chemist s ability to analyse a vast variety of substances. Electron impact spectra from the system are reproducible and can be searched against standard or custom libraries for positive compound identification. Chemical ionization spectra can also be produced. Simplicity is a key feature. A simple adjustment to the particle beam interface is all it takes. 

Coupling of liquid chromatography with mass spectrometry provides unequivocal online spectrometric identification of tetracycline antibiotics in animal-derived foods. Typical applications of mass spectrometry in confirming tetracycline residues in edible animal products describe coupling of liquid chromatography with mass spectrometry via particle-beam (280), electrospray (292), or atmospheric pressure chemical ionization (307), using negative-ion detection interfaces. 

D Hurtaud, B Delepine, P Sanders. Particle-beam liquid chromatography-mass spectrometry method with negative ion chemical ionization for the confirmation of oxacillin, cloxacillin and dicloxacillin residues in bovine muscle. Analyst 119 2731-2736, 1994. 

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. 

C Aguilar, I Ferrer, F Borrull, RM Marce, D Barcelo. Comparison of automated on-line solid-phase extraction followed by liquid chromatography mass spectrometry with atmospheric pressure chemical ionization and particle beam mass spectrometry for the determination of a priority group of pesticides in environmental waters. J Chromatogr A 794 147-163, 1998. 

Recent advances in electrospray ionization (ESI), atmospheric-pressure chemical ionization (APCI), thermospray, and particle beam LC-MS have advanced the analyst toward the universal HPLC detector, but price and complexity are still the primary stumbling blocks. Thus, HPLC-MS remains expensive and the technology has only recently been described. Early commercial LC-MS uses particle beam and thermospray sources, but ESI and APCI interfaces now dominate. Liquid chromatography MS can represent a fast and reliable method for structural analyses of nonvolatile compounds such as phenolic compounds (36,37), especially for low-molecular-weight plant phenolics (38), but the limited resolving power of LC hinders the widespread use of its application for phenolics as compared to GC-MS. 

Over 30 years of liquid chromatography-mass spectrometry (LC-MS) research has resulted in a considerable number of different interfaces (Ch. 3.2). A variety of LC-MS interfaces have been proposed and built in the various research laboratories, and some of them have been adapted by instmment manufacturers and became commercially available. With the advent in the early 1990 s of interfaces based on atmospheric-pressure ionization (API), most of these interfaces have become obsolete. However, in order to appreciate LC-MS, one carmot simply ignore these earlier developments. This chapter is devoted to the older LC-MS interfaces, which is certainly important in understanding the histoiy and development of LC-MS. Attention is paid to principles, instrumentation, and application of the capillary inlet, pneumatic vacuum nebulizers, the moving-belt interface, direct liquid introduction, continuous-flow fast-atom bombardment interfaces, thermospray, and the particle-beam interface. More elaborate discussions on these interfaces can be found in previous editions of this book. 

The particle beam-liquid chromatography-mass spectrometry (PB-L0-M8) of phenols (phenol, 4-nitrophenol, and 1—naphthol) and their glucuronide and sulfate conjugates in electron impact (El) and positive chemical ionization (PCI) is described. 

Jimenez, J. J., Bernal, J. L., Del Nozal, M. J., and Martin, M. T., Use of a particle beam interface combined with mass spectrometry/negative chemical ionization to determine polar herbicide residues in soil by liquid chromatography, J. AOAC Int., 83, 756-761, 2000. 

Figure 3 SPE-LC-APCI-MS chromatogram of 200 ml tap water spiked with 0.04 ng ml of pesticides and 0.05 ng ml IS tert-butylazine in positive-ion mode and dinoterb in negative-ion mode). Peak identification 1, bentazone 2, Vamidothion 3,4-nitrophenol 4, MCPA 5, mecoprop 6, dinoseb 7, atrazine 8, isoproturon 9, ametryn 10, malathion 11, fenotrothion 12, molinate 13, prometryn 14, terbutryn and 15, parathion-ethyl. (Reprinted with permission from Aguilar C, Ferrer I, Bormll F, Marce RM, and Barcelo D (1998) Comparison of automated on-line solid-phase extraction followed by liquid chromatography-mass spectrometry with atmospheric-pressure chemical ionization and particle-beam mass spectrometry for the determination of a priority group of pesticides in environmental waters. Journal of Chromatography A 794 147-163 Elsevier.)...

Stanley, S.M.R Owens, N.A. Rodgers, J.P. Detection of flunixin in equine urine using high-performance liquid chromatography with particle-beam and atmospheric-pressute-ionization mass spectrometry after solid-phase extraction. J. Chromatogr. B, Biomed. Appl. 1995, 667 (1), 95-103. 

Delepine, B. Sanders, P. Determination of chloramphenicol in muscle using a particle beam interface for combining liquid-chromatography with negative-ion chemical ionization mass-spectrometry. J. Chromatogr. 1992, 582, 113-121. 

Compounds with little or no volatility, or thermally labile compounds, are normally introduced through a dynamic interface employing liquid chromatography (LC). The type of LC interface used is dependent on the nature of the process used to ionize the analyte and includes techniques such as particle beam, electrospray, and APCI. Static probe inlets sueh as Maldi, field desorption, desorption chemical ionization (DCI), and FAB can also be used. The details of the individual interfaces will be presented in the section on hyphenated techniques. 

A wide variety of liquid chromatography-mass spectrometry (LC-MS) techniques have been reported for retinoid analysis including direct liquid introduction with Cl (281,282,299-301), particle beam (302-304), thermospray (305-307), electrospray (308,309), and atmospheric pressure chemical ionization (APCI) (310). Because many of the early LC-MS applications to retinoids carried out hydrolysis of retinyl esters and then derivatization of retinoic acid and related retinoids, Wyss (141) predicted in a review of retinoid analysis that derivatization of retinoids would be necessary for all LC-MS techniques, even the anticipated application of atmospheric pressure chemical ionization (APCI). Recently, LC-MS analyses of retinoids have been carried out using APCI (310) and electrospray (308,309), and highly sensitive LC-MS analyses of retinoic acid and retinyl esters were achieved without hydrolysis or derivatization. 

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. 

---