Ion mobility detection following liquid chromatographic separation

Abstract

Abstract. Coronaspray ion mobility spectrometry was used in sample detcction following reversed-phase liquid chromatographic separation. Samples were introduced by coronaspray using a fused silica transfer line that was inserted through a stainless steel needle. Ion mobility spectra and chromatographic responses via monitoring of reactant-ion depletion in the software second gate mode were shown for esters of para-hydroxy benzoic acid, isomers of nitroaniline, and a mixture of acetaminophen, caffeine, and phenacetin. Key words: ion mobility detection. ion mobility spectrometry, HPLC, coronaspruy INTRODUCTIONAlthough many different methods have been employed to detect components following liquid chromatographic separation, ultraviolet (UV) detection is still used most often, even though its response is limited to compounds with appropriate chromophores. Thus, the search continues for sensitive liquid chromatographic detectors that perform reliably and respond to non-light absorbing species, Yeung has summarized the current status of research with regard to detectors that are available for LC (1). As attention shifts to microcolumn LC, the need is increasing for detectors that can detect small quantities of material, are compatible with low flow rates, and will respond to compounds lacking chromophores. Ion mobility spectrometry (IMS) potentially satisfies these three requirements.An ion mobility spectrometer contains an ambient pressure region where a neutral gas is ionized, typically by beta emission from a b3Ni source (2). These ions, called reactant ions, drift through a uniform electric field at velocities that are based on their gas phase mobilities. When small quantities of organic compounds are present near the ionization source, charge transfer processes occur between these neutral organics and the reactant ions and produce a second set of ions called product ions that change the nature of the charge-carrying species in the spectrometer. Use of an orthogonal electric field as a "gate" at either end of a section of the spectrometer allows the drift time of the ions to be determined.

Experimental and Theoretical Investigation of Sodiated Multimers of Steroid Epimers with Ion Mobility-Mass Spectrometry

“…Although historically IM-MS has been used for the study of large biomolecules such as proteins [7–10], recently this technique has been used increasingly for small molecule analysis, primarily due to its rapid millisecond separation capabilities that allow coupling with liquid chromatography [11, 12] and improved analysis of complex samples with mass spectrometry [13, 14]. Additionally, IM-MS offers great potential in rapid separation of isomers that cannot be resolved with mass spectrometry alone.…”

Ammonia as a Modifier in Ion Mobility Spectrometry: Effects on Ion Mobilities and Potential as a Separation Tool

“…IMS was introduced in 1970 by Karasek as detector for volatile organic molecules, 1 and it became the analytical technique preferred for the analysis of explosives, 2 illicit drugs, [3][4][5] and chemical warfare degradation products. [6][7] IMS has been used as a detector for liquid, 8 gas, 9 and supercritical fluid chromatography. 10 IMS has also been applied to the determination of nicotine in tobacco, 11 microorganisms, 12 analysis of protein structures, 13 study of the three-dimensional shape of polyatomic ions, 14 and the separation of isomeric peptides.…”

Pulsed electron beams in ion mobility spectrometry

“…Introduced in the 1960s as an analytical technique to separate and analyze gas phase ions at atmospheric pressure (Eiceman and Karpas 2005 ), ion mobility spectrometers have been developed from fast, sensitive and portal detectors for illegal drugs, explosives, and chemical warfare agents in early stages (McDaniel and Mason 1973, Asbury et al 2000, Ewing et al 2001, Eiceman 2002, Makinen et al 2010 ) over analyzers of non-volatile and labile samples via electrospray ionization-ion mobility spectro metry (ESI-IMS) (Tang et al 2006, Jafari et al 2011, introduced in the late 1980s to analyzers of metabolomes and proteomes if combined with mass spectro metry (McMinn et al 1990, W ü thrich 1993, Chiarello -Ebner 2006, Eckers et al 2007, Liu et al 2007, McLean et al 2007, Waltman et al 2008, Djidja et al 2009, Krueger et al 2009, Armenta et al 2011. In more modern applications, even the study of protein-protein and non-covalent proteinligand complexes is possible (Ruotolo et al 2008, Politis et al 2010.…”