Electrospray-assisted laser desorption

DGE a AC AMS APCI API AP-MALDI APPI ASAP BIRD c CAD CE CF CF-FAB Cl CID cw CZE Da DAPCI DART DC DE DESI DIOS DTIMS EC ECD El ELDI EM ESI ETD eV f FAB FAIMS FD FI FT FTICR two-dimensional gel electrophoresis atto, 10 18 alternating current accelerator mass spectrometry atmospheric pressure chemical ionization atmospheric pressure ionization atmospheric pressure matrix-assisted laser desorption/ionization atmospheric pressure photoionization atmospheric-pressure solids analysis probe blackbody infrared radiative dissociation centi, 10-2 collision-activated dissociation capillary electrophoresis continuous flow continuous flow fast atom bombardment chemical ionization collision-induced dissociation continuous wave capillary zone electrophoresis dalton desorption atmospheric pressure chemical ionization direct analysis in real time direct current delayed extraction desorption electrospray ionization desorption/ionization on silicon drift tube ion mobility spectrometry electrochromatography electron capture dissociation electron ionization electrospray-assisted laser desorption/ionization electron multiplier electrospray ionization electron transfer dissociation electron volt femto, 1CT15 fast atom bombardment field asymmetric waveform ion mobility spectrometry field desorption field ionization Fourier transform Fourier transform ion cyclotron resonance... 

There are some variants that have emerged in the wake of DESI. By replacing the electrospray emitter by a metal needle and allowing solvent vapor into the coaxial gas flow desorption APCI (DAPCI) can be performed [106], Other versions are atmospheric-pressure solids analysis probe (ASAP) where a heated gas jet desorbs the analyte, which is subsequently ionized by a corona discharge [107], and electrospray-assisted laser desorption/ionization (ELDI) where a laser ablates the analyte and charged droplets from an electrospray postionizes the desorbed neutrals [108],... 

J. Shiea, M.-Z. Huang, H.-J. HSu, C.-Y. Lee, C.-H. Yuan, I. Beech, and J. Sunner. Electrospray-Assisted Laser Desorption/Ionization Mass Spectrometry for Direct Ambient Analysis of Solids. Rapid Commun. Mass Spectrom., 19(2005) 3701-3704. 

One of the most significant developments in mass spectrometry in the recent years is the introduction of a new class of ionization methods where samples in either solid or liquid state can be directly ionized in their native environment under ambient conditions (rather than inside a mass spectrometer) without any sample preparation. This new class of ionization methods is often referred to as ambient ionization methods [1,2], Because these methods generally ionize analytes on the surface or near the surface of the samples at atmospheric pressure, they have also been called atmospheric pressure surface sampling/ionization methods or direct/open air ionization methods [3], Since the first reports on ambient ionization with desorption electrospray ionization (DESI) [4] and direct analysis in real time (DART) [5], numerous reports have been published on the applications of these new ionization methods as well as the introduction of many related ambient ionization methods such as desorption atmospheric pressure chemical ionization (DAPCI) [6], atmospheric solid analysis probe (ASAP) [7], and electrospray-assisted laser desorption/ionization (ELDI) [8], Recently, two reviews of the various established and emerging ambient ionization methods have been published [2,3],... 

Shiea, J. et al., Electrospray-assisted laser desorption/ionization mass spectrometry for direct ambient analysis of solids, Rapid Commun. Mass Spectrom., 19, 3701, 2005. 

Several relatively new ionization techniques are derived from the canonical LDI approach. Some of them do not require the use of a vacuum [115-118]. For example, in the first step, neutral species can be desorbed from the condensed phase by a laser light beam, and in the second step, they can be mixed with the charged droplets present in an ESI plume. Several ionization schemes - which bear distinct names - are based on the same concept. For example, electrospray-assisted laser desorption/ionization (ELDI) (Figure 2.17) generally... 

Huang, M.Z., Hsu, H.J., Lee, J.Y., Jeng, J., Shiea, J. (2006) Direct Protein Detection from Biological Media through Electrospray-assisted Laser Desorption loniza-tion/Mass Spectrometry. J. Proteome Res. 5 1107-1116. 

Laser-aided interfaces find applications in fundamental studies in physical chemistry (see Section 4.2.1). However, they can also be used in the monitoring of environmental matrices as well as chemical and biochemical reactions (MA)LDI-MS is the most prominent example (Section 4.2.2). Moreover, laser beams can be introduced into canonical ion sources such as ESI to enable efficient transfer of microscale aliquots of solid or liquid matrices to the ionization zone. Along these lines, Cheng et al. [143] used electrospray-assisted laser desorption/ionization (ELDI) to monitor epoxidation of chalcone in ethanol, chelation of ethylenediaminetetraacetic acid with copper and nickel ions in aqueous solution, chelation of 1,10-phenanthroline with iron(II) in methanol, and... 

Peng, I.X., Ogorzalek Loo, R.R., Shiea, J., Loo, J.A. (2008) Reactive-electrospray-assisted Laser Desorption/Ionization for Characterization of Peptides and Proteins. Anal. Chem. 80 6995-7003. 

ELDI electrospray-assisted laser desorption/ionization... 

Lin, S., Huang, M., Chang, H., Shiea, J. (2007) Using electrospray-assisted laser desorption/ionization mass spectrometry to characterize organic compounds separated on thin-layer chromatography plates. Analytical Chemistry, 79, 8789-8795. 

Thin-Layer Chromatography-Electrospray-Assisted Laser Desorption/... 

THIN-LAYER CHROMATOCRAPHY-ELECTROSPRAY-ASSISTED LASER DESORPTION/IONIZATION... 

Huang, M.Z., Hsu, H.J., Wu, C.I. Lin, S.Y, Ma, Y.L., Cheng, T.L., and Shiea, J. 2007. Characterization of the chemical components on the surface of different solids with electrospray-assisted laser desorption ionization mass spectrometry. Rapid Commun. Mass Spectrom., 21 1767-1775. 

In recent years, TLC was successfully combined with different ionization techniques, matrix-assisted laser desorption/ionization (MALDI), ESI, atmospheric pressure chemical ionization (APCI), desorption electrospray ionization (DESI), electrospray-assisted laser desorption ionization (ELDI), and LDI for identification and quantification of organic and biomolecules. In this section, the interfacing of TLC techniques with MALDI-ESI/MS, DESI-MS, ELSI-MS, and LDI-MS will be described, performance will be discussed, and selected applications in the separation and identification of lipids, gangliosides, dyes, drugs, and medicinal compounds will be presented. 

Ambient MS is another advance in the field. It allows the analysis of samples with little or no sample preparation. Following the introduction of desorption electrospray ionization (DESI) [108,109], direct analysis in real time (DART) [110], and desorption atmospheric pressure chemical ionization (DAPCI) [111, 112], a number of ambient ionization methods have been introduced. They include electrospray-assisted laser desorption/ionization (ELDI) [113], matrix-assisted laser desorption electrospray ionization (MALDESI) [114], atmospheric solids analysis probe (ASAP) [115], jet desorption ionization (JeDI) [116], desorption sonic spray ionization (DeSSI) [117], field-induced droplet ionization (FIDI) [118], desorption atmospheric pressure photoionization (DAPPI) [119], plasma-assisted desorption ionization (PADI) [120], dielectric barrier discharge ionization (DBDI) [121], and the liquid microjunction surface sampling probe method (LMJ-SSP) [122], etc. All these techniques have shown that ambient MS can be used as a rapid tool to provide efficient desorption and ionization and hence to allow mass spectrometric characterization of target compounds. 

The technique of electrospray-assisted laser desorption/ionization (ELDI) combines two well-matured techniques of ionization for the benefit of inproved analysis of samples under ambient conditions. The development of ELDI emanates from the fact that in (MA)LDI by far more neutrals an ions are released from the sample layer (Chap. 11) [45]. Consequently, post-ionization of laser-desorbed neutrals is promising and such methods have indeed been developed (cf. Refs, in [46]). The unique feature of ELDI is to laser-irradiate the sanple in the ambient close to the ESI plume, wherein the neutrals are then ionized by ion-molecule reactions [46]. 

ELDI Electrospray-assisted laser desorption ionization LDI with post-ionization by ESI plume [46]... 

Lin, S.Y. Huang, M.Z. Chang, H.C. Shiea, J. Using Electrospray-Assisted Laser Desorption/Ionization Mass Spectrometry to Characterize Organic Compounds Separated on Thin-Layer Chromatography Plates. Anal. Chem. 2007, 79, 8789-8795. 

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