Characterization of the Microdialysis Junction Interface for Capillary Electrophoresis/Microelectrospray Ionization Mass Spectrometry

Severs, Joanne C.; Smith, Richard D.

doi:10.1021/ac9611226

Cited by 63 publications

(48 citation statements)

References 21 publications

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“…The use of solvent implies that ES MS can be used for on-line detection with LC or CE. Interfacing technology for LC-ES MS is commercially available, whereas interfacing of CE and ES MS is often also performed through laboratory-made constructions (see for example [34] [35,36]). Although some sample preparation is generally required, the on-line capabilities of ES MS have even been applied to in vivo analysis (see for example [37]).…”

Section: 31mentioning

confidence: 99%

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

Baar¹

2000

FEMS Microbiol Rev

176

143

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Section: 31mentioning

confidence: 99%

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

Baar¹

2000

FEMS Microbiol Rev

176

143

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“…Nanoflow LC-MS offers benefits in terms of sensitivity, solvent consumption, and sample consumption when compared with higher flow rate LC-MS, however, it can be much more difficult to operate. Nanoflow sprayers are typically fabricated from tapered fused silica capillary resulting in the need for some type of surface coating [8,9], inserted electrode [10,11], conductive union [6, 12, 13], or dialysis membrane [14] for application of the electrospray potential. Alternatively, sprayers can be fabricated from conductive materials, such as stainless steel, [15], however, tapered stainless steel sprayers are much more difficult to fabricate than fused silica sprayers.…”

mentioning

confidence: 99%

Stable gradient nanoflow LC-MS

Schneider¹,

Guo²,

Fell³

et al. 2005

J. Am. Soc. Mass Spectrom.

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This paper demonstrates improved nanoflow LC-MS performance on a QqTOF instrument with the incorporation of a heated nanoflow interface (particle discriminator) and a nebulizer assisted sprayer. It is shown that the nebulizer broadens the usable range of electrospray potentials, simplifying the tuning procedure, particularly for negative mode nanoflow gradients. The improved desolvation capability with the particle discriminator results in signal/noise improvements of approximately 3.5ϫ for negative ion mode samples prepared in predominantly acidified water as well as increased ion current stability. For nanoLC applications, the combined desolvation capabilities of a counter-current gas and heated laminar flow chamber provide reduced background, increased signal stability, reduced background drift, and improved protein sequence coverage when compared with data generated with only a counter-current gas for desolvation. This system is capable of subfemtomole nanoflow LC-MS sensitivity in both positive and negative ion mode across the solvent gradient. and electrospray ionization-mass spectrometry (ESI-MS) has evolved substantially since its initial implementation in the 1980s [1]. Traditional LC systems operated at solvent flow rates that were orders of magnitude higher (hundreds of L/min to mL/min) than those used for mass spectrometry (tens of L/ min), resulting in the need for solvent flow splitters [2]. Some of the subsequent improvements were focused on the use of nebulizer gases [3] and heating [4,5] for stabilization of the electrospray process to accommodate higher LC solvent flows.An alternate approach involves modification of the LC system to accommodate separations within the nanoflow regime [6,7]. Nanoflow LC-MS offers benefits in terms of sensitivity, solvent consumption, and sample consumption when compared with higher flow rate LC-MS, however, it can be much more difficult to operate. Nanoflow sprayers are typically fabricated from tapered fused silica capillary resulting in the need for some type of surface coating [8,9], inserted electrode [10,11], conductive union [6, 12, 13], or dialysis membrane [14] for application of the electrospray potential. Alternatively, sprayers can be fabricated from conductive materials, such as stainless steel, [15], however, tapered stainless steel sprayers are much more difficult to fabricate than fused silica sprayers. An additional benefit associated with fused silica sprayers is that the analytical column may be packed directly into the tapered sprayer, eliminating any post-column dead volume [16,17].A necessary but understated requirement for gradient elution in nanoLC-MS is an electrospray system that is capable of stable operation over a wide range of solvent compositions, particularly for samples containing both hydrophilic and hydrophobic components. Typical nanoflow electrospray systems display good stability for samples consisting of 20 to 100% organic solvent. However, stability can be an issue when running predominantly aqueous solvents because of the h...

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“…Typically these reduced flow rate ESI sources provide improved signal stability and sampling efficiency when compared to higher flow rate ESI sources. However they require the use of tapered capillaries with a metal coating [5], incapillary electrode [14], or some other type of junction [8,15,16] for applying the electrospray potential.High flow rate electrospray ion sources are easy to operate, but typically suffer from a lower sampling efficiency and poorer signal stability when compared with reduced flow rate electrospray ion sources. This problem is accentuated when spraying samples with high aqueous content.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

An atmospheric pressure ion lens that improves nebulizer assisted electrospray ion sources

Schneider

Douglas

Chen

2002

J. Am. Soc. Mass Spectrom.

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An atmospheric pressure ion lens improves the performance and ease of use of a nebulizer assisted electrospray (ion spray) ion source. The lens is comprised of an oblong-shaped stainless steel ring attached to an external high voltage power supply. The lens is located near the tip of the conductive sprayer, and is maintained at a potential less than that of the sprayer. The ion lens improves the shape of the equipotential lines in the vicinity of the sprayer tip. This lens gives approximately a 2-fold reduction in the signal RSD, a 2-fold increase in the ion signal, an increase in the number of multiply charged ions, and a much broader range of usable sprayer positions. , is a versatile technique for the formation of gas phase ions for mass spectrometry. In these early studies, the sprayer was stainless steel syringe tubing with an internal diameter of 100 m, and the solution flow rates were a few L/min or greater. Since then, ESI has been used extensively for many applications including analysis of drugs [2], proteins [3], and oligonucleotides [4], to name a few. A key concern in many of these types of analyses is maximizing the magnitude and stability of the ion signal.Electrospray ion sources can be operated over a wide range of solution flow rates, including high flow rate (Ն1 L/min), reduced flow rate (80 nL/min-1 L/ min), and very low flow rate (Ͻ80 nL/min). Wilm and Mann described the first ESI source for operation at very low liquid flow rates (Ϸ20 nL/min) [5]. Stabilization of electrospray at this flow rate required the use of tapered capillary tips, with internal diameters of 1-2 m. A thin layer of gold was deposited on the glass capillary tips for application of the electrospray potential. This technique was termed nanoelectrospray ionization. Sampling efficiency was increased, however operation with the tapered tips was more difficult than electrospray at higher flow rates.The first description of electrospray operating as a reduced flow rate ion source was by Smith and coworkers [6], in which a capillary electrophoresis system was coupled with a mass spectrometer. Shortly thereafter, Emmett et al. described a packed electrospray needle for interfacing chromatography with mass spectrometry at low flow rates (300 nL/min and above) [7]. Following these initial experiments, there have been many studies with electrospray operating in this flow regime for applications involving direct infusion [8,9], or the coupling of CE [10,11] and LC [12,13] with ESI-MS. Typically these reduced flow rate ESI sources provide improved signal stability and sampling efficiency when compared to higher flow rate ESI sources. However they require the use of tapered capillaries with a metal coating [5], incapillary electrode [14], or some other type of junction [8,15,16] for applying the electrospray potential.High flow rate electrospray ion sources are easy to operate, but typically suffer from a lower sampling efficiency and poorer signal stability when compared with reduced flow rate electrospray ion sources. This problem i...

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Characterization of the Microdialysis Junction Interface for Capillary Electrophoresis/Microelectrospray Ionization Mass Spectrometry

Cited by 63 publications

References 21 publications

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

Characterisation of bacteria by matrix-assisted laser desorption/ionisation and electrospray mass spectrometry

Stable gradient nanoflow LC-MS

An atmospheric pressure ion lens that improves nebulizer assisted electrospray ion sources

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