Ambient Mass Spectrometry

Cooks, R. Graham; Ouyang, Zheng; Takáts, Zoltán; Wiseman, Justin M.

doi:10.1126/science.1119426

Cited by 1,327 publications

(1,072 citation statements)

References 27 publications

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“…Analytes present at the surface are desorbed and ionized by the incoming plume and subsequently transferred to the mass spectrometer inlet by the influence of the applied potential and the pressure differential between atmospheric pressure and the low-pressure region of the mass analyzer. To date, DESI has found many applications including forensic analysis [2][3][4][5], explosives detection [6 -9], chemical warfare agent detection [3, 10 -12], imaging [13][14][15], pharmaceutical analysis [16 -24], natural product characterization [2,25], polymer analysis [26,27], metabolomics [2, 28 -31], proteomics [2,[32][33], and glycomics [34].…”

Section: Esorption Electrospray Ionization (Desi)mentioning

confidence: 99%

The influence of material and mesh characteristics on transmission mode desorption electrospray ionization

Chipuk

Brodbelt

2008

J. Am. Soc. Mass Spectrom.

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Adaptation of desorption electrospray ionization to a transmission mode (TM-DESI) entails passing an electrospray plume through a sample that has been deposited onto a mesh substrate. A combination of mass spectrometry and fluorescence microscopy studies is used to illustrate the critical role material composition, mesh open space, and mesh fiber diameter play on the transmission, desorption, and ionization process. Substrates with open spaces less than 150 m and accompanying minimal strand diameters produce less scattering of the plume and therefore favor transmission. Larger strand diameters typically encompass larger open spaces, but the increase in the surface area of the strand increases plume scattering as well as solvent and analyte spreading on the mesh. Polypropylene (PP), ethylene tetrafluoroethylene (ETFE), and polyetheretherketone (PEEK) materials afford much better desorption than similarly sized polyethylene terephthalate (PETE) or nylon-6,6 (PA66) substrates. Ultimately, the manner in which the electrospray plume interacts with the mesh as it is transmitted through the substrate is shown to be critical to performing and optimizing TM-DESI analyses. In addition, evidence is presented for analyte dependent variations in the desorption mechanisms of dry and solvated samples. . In DESI, ions are produced by directing charged solvent droplets from an electrospray source toward a sample that is either a bulk material in its native state (e.g., pharmaceutical tablet) or one that has been deposited from solution onto a sampling surface. Analytes present at the surface are desorbed and ionized by the incoming plume and subsequently transferred to the mass spectrometer inlet by the influence of the applied potential and the pressure differential between atmospheric pressure and the low-pressure region of the mass analyzer. To date, DESI has found many applications including forensic analysis [2][3][4][5] Recent adaptations of DESI, including geometry independent DESI in gas tight enclosures [35] and transmission mode desorption electrospray ionization (TM-DESI), have been developed to reduce the geometry dependence of DESI experiments [36]. In the transmission DESI mode the sample is not deposited onto a continuous solid surface but rather onto a sampling mesh. In this adaptation, the incident spray angle and collection angle are fixed at 0°and the spray is transmitted through the sample (Figure 1). Along with the simplification of the experimental geometry, the transmission mode also allows convenient analysis of both dry (i.e., following evaporation of the deposition solvent) and wet (i.e., solvated) samples with similar performance characteristics to those achieved using traditional DESI [36].Surface variables including the chemical composition, porosity, texture, and electrical conductivity of the substrate have been reported to affect DESI analyses [2,24,[37][38][39]. Dramatic reductions in response have been noted for high conductivity surfaces due to neutralization of the incoming ion plume at the su...

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Section: Esorption Electrospray Ionization (Desi)mentioning

confidence: 99%

The influence of material and mesh characteristics on transmission mode desorption electrospray ionization

Chipuk

Brodbelt

2008

J. Am. Soc. Mass Spectrom.

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“…ionization technique in which the sample of interest is examined in the ordinary ambient environment [1,2]. The method involves electrospraying a solvent to generate charged microdroplets that impact a condensed-phase sample and extracts analyte molecules in situ.…”

Section: Esorption Electrospray Ionization (Desi) Is Anmentioning

confidence: 99%

“…Using typical DESI conditions [1,2], 3 L sample solutions containing varying concentrations of salt were analyzed from a variety of surfaces. Samples spotted onto porous surfaces tend to spread over a larger area (ϳ12 mm 2 ) than those on smooth surfaces (ϳ3 mm 2 ).…”

Section: Mass Spectrometrymentioning

confidence: 99%

Salt tolerance of desorption electrospray ionization (DESI)

Jackson

Talaty

Cooks

et al. 2007

J. Am. Soc. Mass Spectrom.

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The salt tolerance of desorption electrospray ionization (DESI) was systematically investigated by examining three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl (1:1) from different surfaces. At physiological salt concentrations, the individual drugs in each mixture were observed in each experiment. Even at salt concentrations significantly above physiological levels, particular surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest in low nanogram amounts. Salt adducts, which are observed even in the absence of added salt, could be eliminated by adding 0. . The method involves electrospraying a solvent to generate charged microdroplets that impact a condensed-phase sample and extracts analyte molecules in situ. Secondary droplets containing analyte ions are sucked by the vacuum into the atmospheric sampling interface of a mass spectrometer. In various cases, complex biological mixtures have been analyzed successfully with little or no sample preparation [3][4][5][6][7][8][9]. In these and other previous studies, the preliminary indications were that DESI has a high salt tolerance. These studies did not explore the limits of this tolerance as a function of salt concentration, nor were the effects of the nature of the substrate or the possibility that additives in the spray solution might prevent the formation of salt adducts studied. Each of these enquiries is undertaken here.The underlying reasons for ion suppression effects has been a subject of interest in several electrospray ionization (ESI) mass spectrometry studies [10 -14]. A mechanistic investigation into this phenomenon concluded that it is more likely to occur in the liquid than in the gas phase, and that it can be ascribed to the presence of high concentrations of non-volatile compounds, such as salts and endogenous metabolites [10,[12][13][14]. Non-volatile materials like salts alter the efficiency of droplet formation, which in turn negatively affects the number of ions reaching the mass spectrometer. In highly concentrated samples (Ͼ10 Ϫ5 M), there is competition among analyte ions during droplet formation for outer surface space and this is believed to contribute to ion suppression [11]. Ion suppression is also thought to occur due to the masking of analytes by matrix ions of greater polarity or even by high mass compounds masking lower mass analytes [10,12].The successes of DESI in a large variety of applications [4,6,[15][16][17][18][19] are partly due to the availability of various surfaces from which the sample can be analyzed and, even more important, due to the ability to optimize the spray solvent for the analyte(s) of interest. Addition of a selective reagent to the solvent spray can be used to enhance the analyte signal by an appropriate chemical reaction; an experiment that is termed reactive DESI [20 -22]. By the inverse argument, possibly appropriate reagents added to the spray solution might reduce signals due to unwanted ions; such an action wou...

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“…A range of applications, including 2D imaging of small molecules and metabolites released from tissue cross‐sections, has become possible with the introduction of powerful DESI approaches when coupled with MS 1, 2. The primary goal of DESI applications has been to focus on the small molecules released, for example in the real‐time detection of tumour tissue during surgical procedures 3, 4.…”

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confidence: 99%

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

et al. 2017

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Mass spectrometry (MS) applications for intact protein complexes typically require electrospray (ES) ionization and have not been achieved via direct desorption from surfaces. Desorption ES ionization (DESI) MS has however transformed the study of tissue surfaces through release and characterisation of small molecules. Motivated by the desire to screen for ligand binding to intact protein complexes we report the development of a native DESI platform. By establishing conditions that preserve non‐covalent interactions we exploit the surface to capture a rapid turnover enzyme–substrate complex and to optimise detergents for membrane protein study. We demonstrate binding of lipids and drugs to membrane proteins deposited on surfaces and selectivity from a mix of related agonists for specific binding to a GPCR. Overall therefore we introduce this native DESI platform with the potential for high‐throughput ligand screening of some of the most challenging drug targets including GPCRs.

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Ambient Mass Spectrometry

Cited by 1,327 publications

References 27 publications

The influence of material and mesh characteristics on transmission mode desorption electrospray ionization

The influence of material and mesh characteristics on transmission mode desorption electrospray ionization

Salt tolerance of desorption electrospray ionization (DESI)

Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

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