A Study of Electrospray Ionization Emitters with Differing Geometries with Respect to Flow Rate and Electrospray Voltage

Reschke, Brent R.; Timperman, Aaron T.

doi:10.1007/s13361-011-0251-4

Cited by 26 publications

(15 citation statements)

References 71 publications

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“…The response appears to be flow rate sensitive at low flow rates (30–200 nL/min) and concentration sensitive at high flow rates (>200 nL/min). A similar trend was reported using a fused silica emitter with a 50 μm id and an etched od . In the flow rate sensitive region, ionization efficiency improved at very low flow rates .…”

Section: Resultssupporting

confidence: 80%

Sheathless capillary electrophoresis electrospray ionization‐mass spectrometry interface based on poly(dimethylsiloxane) membrane emitter and thin conducting liquid film

Wang

Her

2013

Electrophoresis

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This study develops a sheathless CE-MS interface using a robust PDMS membrane emitter and liquid-film electric conduction. A 3D mold was constructed for casting the device by using a one-step casting procedure. The interface consisted of a 125 μm-thick triangular emitter with a 50 μm-diameter microchannel, a conducting reservoir, and a 375 μm-diameter channel for assembling the separation capillary. The separation capillary was inserted into the 375 μm channel and connected to the emitter through the conducting reservoir. The electric contact for the CE outlet was established through a conductive liquid film in the space between the capillary terminus and the 375 μm channel. The one-step casting procedure and using a membrane emitter instead of a tapered emitter produced an easily fabricated and robust interface. A stable electrospray was obtained from 30 to 350 nL/min. Analyzing a five-peptide mixture in low-EOF (60 nL/min) and high-EOF (210 nL/min) conditions demonstrated the utility of the interface.

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Section: Resultssupporting

confidence: 80%

Sheathless capillary electrophoresis electrospray ionization‐mass spectrometry interface based on poly(dimethylsiloxane) membrane emitter and thin conducting liquid film

Wang

Her

2013

Electrophoresis

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“…Low flow rates have been reported to increase ion intensity [61]. The flow rate in our ESI experiments was ~2.5 μL/min, while the nanoESI flow rate was ~0.2 μL/min.…”

Section: Resultsmentioning

confidence: 97%

The Use of Chromium(III) to Supercharge Peptides by Protonation at Low Basicity Sites

Feng

Commodore

Cassady

2014

J. Am. Soc. Mass Spectrom.

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The addition of chromium(III) nitrate to solutions of peptides with seven or more residues greatly increases the formation of doubly protonated peptides, [M+2H]2+, by electrospray ionization. The test compound heptaalanine has only one highly basic site (the N-terminal amino group) and undergoes almost exclusive single protonation using standard solvents. When Cr(III) is added to the solution, abundant [M+2H]2+ forms, which involves protonation of the peptide backbone or the C-terminus. Salts of Al(III), Mn(II), Fe(III), Fe(II), Cu(II), Zn (II), Rh(III), La(III), Ce(IV), and Eu(III) were also studied. While several metal ions slightly enhance protonation, Cr(III) has by far the greatest ability to generate [M+2H]2+. Cr(III) does not supercharge peptide methyl esters, which suggests that the mechanism involves interaction of Cr(III) with a carboxylic acid group. Other factors may include the high acidity of hexaaquochromium(III) and the resistance of Cr(III) to reduction. Nitrate salts enhance protonation more than chloride salts and a molar ratio of 10:1 Cr(III):peptide produces the most intense [M+2H]2+. Cr(III) also supercharges numerous other small peptides, including highly acidic species. For basic peptides, Cr(III) increases the charge state (2+ versus 1+) and causes the number of peptide molecules being protonated to double or triple. Chromium(III) does not supercharge the proteins cytochrome c and myoglobin. The ability of Cr(III) to enhance [M+2H]2+ intensity may prove useful in tandem mass spectrometry because of the resulting overall increase in signal-to-noise ratio, the fact that [M+2H]2+ generally dissociate more readily than [M+H]+, and the ability to produce [M+2H]2+ precursors for electron-based dissociation techniques.

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“…Herein, despite using a smaller particle stationary phase (3.5 µm particle size) and acetonitrile as an eluent, the chromatogram performance improved; the findings suggest that the gradient eluent plays a key role in the efficiency of gallic acid detection and the enhanced content of gallic acid. Studies have shown the influence of gradient elution using increased acetonitrile and flow rate modification [56,57]. Increasing flow rate can lead to faster elution of analytes, whereas decreasing flow rate results in better resolution and improved concentration-sensitive detection.…”

Section: Hplc Methods Validationmentioning

confidence: 99%

Development of a Simple High-Performance Liquid Chromatography-Based Method to Quantify Synergistic Compounds and Their Composition in Dried Leaf Extracts of Piper Sarmentosum Roxb.

Purba

Paengkoum

2021

Separations

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There is a growing demand to enhance pharmaceutical and food safety using synergistic compounds from Piper sarmentosum Roxb., such as polyphenols and water-soluble vitamins. However, information on standardized analytical methods to identify and quantify these compounds of interest is limited. A reversed-phase high-performance liquid chromatography with diode-array detection (HPLC-DAD)-based method was developed to simultaneously detect and quantify the amounts of tannin, flavonoid, cinnamic acid, essential oil, and vitamins extracted from P. sarmentosum leaves using methanol, chloroform, and hexane. Commercially and non-commercially-cultivated P. sarmentosum leaves were subjected to seven different drying treatments (shade; sun; air oven at 40 °C, 60 °C, 80 °C, and 100 °C; and freeze-drying) for three consecutive months. Most compounds were detected most efficiently at a detection wavelength of 272 nm. The developed method displayed good detection limits (LOD, 0.026–0.789 µg/mL; LOQ, 0.078–2.392 µg/mL), linearity (R2 > 0.999), precision (%RSD, <1.00), and excellent accuracy (96–102%). All P. sarmentosum leaf extracts were simultaneously tested and analytically compared without time-consuming fractionation. Methanolic plant extracts showed better peak area and retention time splits compared to chloroformic and hexanoic extracts. Differences in synergistic compound composition were dependent on the type of drying treatment but not on cultivation site and time of sampling. Flavonoid was identified as the dominant phytochemical component in P. sarmentosum leaves, followed by the essential oil, cinnamic acid, ascorbic acid, and tannin. Overall, we present a simple and reproducible chromatographic method that can be applied to identify different plant compounds.

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A Study of Electrospray Ionization Emitters with Differing Geometries with Respect to Flow Rate and Electrospray Voltage

Cited by 26 publications

References 71 publications

Sheathless capillary electrophoresis electrospray ionization‐mass spectrometry interface based on poly(dimethylsiloxane) membrane emitter and thin conducting liquid film

Sheathless capillary electrophoresis electrospray ionization‐mass spectrometry interface based on poly(dimethylsiloxane) membrane emitter and thin conducting liquid film

The Use of Chromium(III) to Supercharge Peptides by Protonation at Low Basicity Sites

Development of a Simple High-Performance Liquid Chromatography-Based Method to Quantify Synergistic Compounds and Their Composition in Dried Leaf Extracts of Piper Sarmentosum Roxb.

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