• 제목/요약/키워드: electrospray mass spectrometry

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Dual Nano-Electrospray and Mixing in the Taylor Cone

  • Radionova, Anna;Greenwood, David R.;Willmott, Geoff R.;Derrick, Peter J.
    • Mass Spectrometry Letters
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    • 제7권1호
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    • pp.21-25
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    • 2016
  • Dual-channel nano-electrospray has recently become an ionization technique of great promise especially in biological mass spectrometry. This unique approach takes advantage of the mixing processes that occurs during electrospray. Understanding in more detail the fundamental principles influencing spray formation further study of the origins of the mixing processes: (1) in a Taylor cone region, (2) in charged droplets or (3) in both environments. The dual-channel emitters were made from borosilicate theta-shape glass tubes (O.D. 1.2 mm) and had a tip diameters of less than 4 μm. Electrical contact was achived by deposition of a thin film of an appropriate metal onto the surface of the emitter. The experimental investigation of the Taylor cone formation in a dual-channel electrospray emitter has been carried out by injection of polystyrene beads (diameter 3 μm) at very low concentrations into one of the channels of the non-tapered theta-glass tubes. High-speed camera experiments were set up to visualize the mixing processes in Taylor cone regions for dual-channel emitters. Mass spectra from dual nano-electrospray are presented.

Hydrolysis of Penicillin G and Carbenicillin in Pure Water - As Studied by HPLC/ESI-MS

  • Kolek, Marta;Franski, Rafal;Franska, Magdalena
    • Mass Spectrometry Letters
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    • 제10권4호
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    • pp.108-111
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    • 2019
  • The hydrolysis of penicillin G, carbenicillin and ampicillin in pure water at room temperature was studied by high pressure liquid chromatography electrospray ionization mass spectrometry. Hydrolysis of ampicillin did not occur under these conditions; however, penicillin G and carbenicillin were completely hydrolyzed after seven days. A short interpretation of this difference is proposed. The mass spectrometric behaviour, namely ESI response and fragmentation pathway, of hydrolyzed penicillin G and hydrolyzed carbenicillin have been also discussed.

General Fragmentations of Alkaloids in Electrospray Ionization Tandem Mass Spectrometry

  • Shim, Hee Jung;Lee, Ji Ye;Kim, Byungjoo;Hong, Jongki
    • Mass Spectrometry Letters
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    • 제4권4호
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    • pp.79-82
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    • 2013
  • Various types of alkaloids observed in several herbal medicines were analyzed by electrospray ionization tandem mass spectrometry in positive ion mode. In the present study, MS/MS spectralpatterns were investigated for eight-types of alkaloids (aporpine, protoberberine, tetrahydroprotoberberine, benzylisoquinoline, protopine, phthalide, morpine, and bisbenzylisoquinoline). For aporpine- and protoberberine-type alkaloids, main fragmentations occurred at substituted groups on rigid ring structures, not showing ring fusion. Interesting fragmentations due to iminolization and retro-Diels-Alder (RDA) reaction were observed in MS/MS spectra of protopine- and tetrahydroprotobereberine-type alkaloids. Also, several types of fragmentations such as inductive cleavage and ${\alpha}$-cleavage, or bond cleavage between two ring structures were observed depending on their structural characteristics. These fragmentation patterns are expected to allow instant classification of the specific alkaloid type in various MS/MS spectra of alkaloids.

Soft Ionization of Metallo-Mefenamic Using Electrospray Ionization Mass Spectrometry

  • Abdelhamid, Hani Nasser;Wu, Hui-Fen
    • Mass Spectrometry Letters
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    • 제6권2호
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    • pp.43-47
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    • 2015
  • Detection of mefenamic acid (M, non-steroidal anti-inflammatory drug, NSAIDs) and its metallodrug was investigated using electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. ESI-MS data (500 µL, 1×10-3 M) revealed high detection sensitivity for the drug and metallodrug. ESI-MS spectra revealed peaks at 242, 580, and 777 Da corresponding to [M+H]+, [63Cu(M-H)2(H2O)2+H]+, and [56Fe(M-H)3+H]+, respectively. The metal:mefenamic ratios of ESIMS spectra are in complete agreement with the fluorescence spectroscopy results (1:2 for Cu(II) and 1:3 for Fe(III)). ESI is a soft ionization technique that can be used on labile metallo-mefenamic acids and is promising for the detection of these species in environmental samples and biological fluids.

Development of a Four-way Interface for Online Capillary Isoelectric Focusing-Electrospray-Mass Spectrometry (CIEF-ESI-MS)

  • Yu, Hai Dong;Kim, Byungjoo;Shin, Dae-Ho;Ahn, Seonghee
    • Mass Spectrometry Letters
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    • 제4권4호
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    • pp.83-86
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    • 2013
  • A new interface for coupling CIEF and MS using a four-way cross has been developed in a single mechanical system. This new interface could be operated without the electric discontinuity and reinstallation of lines. Additionally, a bare fused silica capillary was facilitated as a spray needle to produce electrospray and to guide catholyte or sheath liquid. Focusing for CIEF was completed in a hanging droplet at the end of spray needle. This capillary spray needle also provided stable spray, enhanced the ionization efficiency and increased sensitivity. Results with carbonic anhydrase I showed that focusing and spraying were well completed with the new interface and the new spray needle.

Identification of Ceftiofur Oxidation Products by High-Performance Liquid Chromatography/Electrospray Ionization/Tandem Mass Spectrometry

  • Lim, Young-Hee;Park, Deok-Hie;Youn, Yeu-Young;Kim, Kyung-Hoon;Cho, Hye-Sung
    • Mass Spectrometry Letters
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    • 제2권1호
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    • pp.16-19
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    • 2011
  • Oxidation products of ceftiofur were formed in hydrogen peroxide solution. The structures of the ceftiofur oxidation products were characterized by high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry (HPLC/ESI/MS/MS). The products were identified as compounds oxidized at the sulfur of a cephem ring. For further analysis, experiments were performed using $O^{18}$-labeled hydrogen peroxide. In addition, density-functional calculations were carried out for six possible oxidation products to support the experimental results.

Determination of Enalapril in Human Plasma by High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry

  • Yoon, Kyung-Hwan;Kim, Won;Park, Jong-Sei;Kim, Hie-Joon
    • Bulletin of the Korean Chemical Society
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    • 제25권6호
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    • pp.878-880
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    • 2004
  • Revered-phase LC-electrospray ionization mass spectrometry was used to selectively determine enalapril from plasma with minimal sample preparation. Detection limit of the method was 1 ng/mL. Precision (within day and between days) and accuracy of the method at various concentrations were acceptable. The analytical technique was used for pharmacokinetic studies after administration of enalapril to human test subjects.

Comparison of Lipid Profiles in Head and Brain Samples of Drosophila Melanogaster Using Electrospray Ionization Mass Spectrometry (ESI-MS)

  • Jang, Hyun Jun;Park, Jeong Hyang;Lee, Ga Seul;Lee, Sung Bae;Moon, Jeong Hee;Choi, Joon Sig;Lee, Tae Geol;Yoon, Sohee
    • Mass Spectrometry Letters
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    • 제10권1호
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    • pp.11-17
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    • 2019
  • Drosophila melanogaster (fruits fly) is a representative model system widely used in biological studies because its brain function and basic cellular processes are similar to human beings. The whole head of the fly is often used to obtain the key function in brain-related diseases like degenerative brain diseases; however the biomolecular distribution of the head may be slightly different from that of a brain. Herein, lipid profiles of the head and dissected brain samples of Drosophila were studied using electrospray ionization-mass spectrometry (ESI-MS). According to the sample types, the detection of phospholipid ions was suppressed by triacylglycerol (TAG), or the specific phospholipid signals that are absent in the mass spectrum were measured. The lipid distribution was found to be different in the wild-type and the microRNA-14 deficiency model ($miR-14{\Delta}^1$) with abnormal lipid metabolism. A few phospholipids were also profiled by comparison of the head and the brain in two fly model systems. The mass spectra showed that the phospholipid distributions in the $miR-14{\Delta}^1$ model and the wild-type were different, and principal component analysis revealed a correlation between some phospholipids (phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS)) in $miR-14{\Delta}^1$. The overall results suggested that brain-related lipids should be profiled using fly samples after dissection for more accurate analysis.