• Journal of Life Science
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• v.29 no.2
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• pp.198-201
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• 2019

Recently, it has been reported that Bacillus mojavensis possesses antifungal properties and plant growth-promoting activities, which are similar to the characteristics of siderophore. In this study, the siderophore produced by B. mojavensis was assessed using a solid phase extraction (SPE) cartridge and liquid chromatography quadrupole time-of-flight tandem mass spectrometry (Q-TOF MS/MS). After B. mojavensis was incubated in phenol medium for 16 hr and lyophilized, the sample was dissolved in water and loaded to an SPE cartridge to remove interferences. The cartridge was washed with 5% methanol in water and eluted with 2% formic acid in methanol sequentially. The eluted solution was evaporated under a stream of nitrogen gas and reconstituted in methanol. The reconstituted sample was filtered, and $1{\mu}l$ of the sample was assessed using Q-TOF MS/MS. The mass spectrometer was operated using the positive electrospray ionization mode. Based on the mass spectrum and tandem mass spectrum, the siderophore produced by B. mojavensis was bacillibactin, one of the catechol types of siderophore with a molecular weight of 882.2556. This siderophore analysis could provide a justification for the study of B. mojavensis as a functional food and for pharmaceutical applications.

• Toxicological Research
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• v.29 no.3
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• pp.203-209
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• 2013

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ${\varepsilon}$-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX $C_{18}$ column ($150mm{\times}2.0mm$, i.d., 3 ${\mu}m$ particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 ${\mu}l/min$. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from -8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1124-1131
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• 2016

In this study, the global proteome of the IPEC-J2 cell line was evaluated using ultra-high performance liquid chromatography coupled to a quadrupole Q Exactive^™ Orbitrap mass spectrometer. Proteins were isolated from highly confluent IPEC-J2 cells in biological replicates and analyzed by label-free mass spectrometry prior to matching against a porcine genomic dataset. The results identified 1,517 proteins, accounting for 7.35% of all genes in the porcine genome. The highly abundant proteins detected, such as actin, annexin A2, and AHNAK nucleoprotein, are involved in structural integrity, signaling mechanisms, and cellular homeostasis. The high abundance of heat shock proteins indicated their significance in cellular defenses, barrier function, and gut homeostasis. Pathway analysis and annotation using the Kyoto Encyclopedia of Genes and Genomes database resulted in a putative protein network map of the regulation of immunological responses and structural integrity in the cell line. The comprehensive proteome analysis of IPEC-J2 cells provides fundamental insights into overall protein expression and pathway dynamics that might be useful in cell adhesion studies and immunological applications.

• Analytical Science and Technology
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• v.22 no.2
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• pp.152-158
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• 2009

In this study, we made a new discharge source improving previous SPI source to ionize softly organic compounds. The new SPI source consists of two electrodes as a hollow mesh cathode of half cylindrical shape and a hollow anode. We optimized the geometrical parameter of the SPI source by investigating the I-V curves at the various distance between the cathode and the anode. As the results, we found stable conditions of the soft plasma on broad range of the current and the voltage. The new SPI source attached to quadrupole mass spectrometer (QMS), and we obtained the mass spectra of dichloromethane (DCM). The fragment patterns of DCM appeared similarly with the pattern of electron ionization (EI).

• Journal of the Korean institute of surface engineering
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• v.38 no.2
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• pp.73-78
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• 2005

A real-time monitoring of ICP(inductively coupled plasma) assisted magnetron sputtering of MgO was carried out using a QMS(quadrupole mass spectrometer), an OES(optical emission spectrometer), and a digital oscilloscope with a high voltage probe and a current monitor. At the time of ICP ignition, the most distinct impurity was OH emission (308.9 nm) which was dissociated from water molecules. For reactive deposition oxygen was added to Ar and the OH emission intensity was reduced abruptly When the discharge voltage was regulated by a PID controller from 240V(metallic mode) to 120V(oxide mode), the emission intensity from Mg (285.2 nm) changed proportionally to the discharge voltage, but the intensity of Ar I(811.6 nm) was constant. At 100V of discharge voltage, Mg sputtering was almost stopped. Emissions from Ar I(420.1 nm) and Mg I were dropped down to 1/10, but Ar I(811.6 nm) didn't change. And the emission from atomic oxygen (O I, 777.3 nm) was increased to 10 times. These results are compatible with those from QMS study.

• Mass Spectrometry Letters
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• v.3 no.2
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• pp.39-42
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• 2012

Phosphorylation and glycosylation are two of the most important and widespread post-translational modifications (PTMs) in an organism. Proteomics analysis of the PTMs has been challenged by low stoichiometry of the modified proteins and suppression effects by high abundance proteins, typically no-functional house-keeping proteins. In this study, a novel method was applied for not only isolating PTM peptides from intact peptides but also concurrently characterizing of glyco- and phosphoproteome using electrostatic repulsion hydrophilic interaction chromatography (ERLIC) packed with silica coated by crosslinked polyethyleneimine. For 2 mg tryptic digest of mouse proteome of epicardial adipose tissue with fat diet, 802 N-glycosylated peptides of 316 glycoproteins and 159 phosphorylated peptides of 75 phosphoproteins were identified using HPLC chip/quadrupole time-of-flight (Q-OF) tandem mass spectrometer.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.382-394
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• 2016

Background: Ginsenosides are the characteristic and principal components which manifest a variety of the biological and pharmacological activities of the roots and rhizomes of Panax ginseng (GRR). This study was carried out to qualitatively and quantitatively determine the ginsenosides in the cultivated and forest GRR. Methods: A rapid and sensitive ultra-high-performance liquid chromatography coupled with diode-array detector and quadrupole/time of flight tandem mass spectrometry (UPLC-DAD-QTOF-MS/MS) was applied to the qualitative analysis of ginsenosides and a 4000 QTRAP triple quadrupole tandem mass spectrometer (HPLC-ESI-MS) was applied to quantitative analysis of 19 ginsenosides. Results: In the qualitative analysis, all ingredients were separated in 10 min. A total of 131 ginsenosides were detected in cultivated and forest GRR. The method for the quantitative determination was validated for linearity, precision, and limits of detection and quantification. 19 representative ginsenosides were quantitated. The total content of all 19 ginsenosides in the forest GRR were much higher than those in the cultivated GRR, and were increased with the growing ages. Conclusion: This newly developed analysis method could be applied to the quality assessment of GRR as well as the distinction between cultivated and forest GRR.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.59-65
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• 1997

Efficient Si(100) etching by thermal H atoms at low substrate temperatures has been achieved. Gas-phase etching product $SiH_4$(g) upon H atom bombardment resulting from direct abstraction of $SiH_3$(a) by impinging H atoms was detected with a quadrupole mass spectrometer over the substrate temperature range of 105-408 K Facile depletion of all surface silyl ($SiH_3$) groups the dissociative adsorption product of disilane ($Si_2H_6$) at 105K from Si(100)2$\times$1 by D atoms and continuous regeneration and removal of $SiD_3$(a) were all consumed. These results provide direct evidence for efficient silicon surface etching by thermal hydrogen bombardment at cryogenic temperatures as low as 105K We attribute the high etching efficiency to the formation and stability of $SiH_3$(a) on Si(100) at lowered surface temperatures allowing the $SiH_3$(a) abstraction reaction by additional H atom to produce $SiH_4$((g).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.73-73
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• 2008

In this work, the study on the $SiO_2$ film non-uniformity by PECVD (Plasma Enhanced Chemical Vapor Deposition) was performed. Plasma diagnostics was analyzed by a DLP(Double Langmuir Probe) and a probe-type QMS(Quadrupole Mass Spectrometer) in order to investigate the spatial distribution of the plasma species in the chamber. The relationship between the plasma species and the depositing rate of the films was examined. On the basis of this work, it was confirmed that O radical density mainly contributed to the increase in the depositing rate of the $SiO_2$ films and the electron temperature in the plasma had a main effect on the formation of the oxygen radicals.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.197-200
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• 2001

Novel Enhanced Inductively Coupled Plasma is applied to etch $SiO_2$. Effect of $O_2$ or Ar addition to $C_{4}F_{8}$ gas is monitored by Optical Emission Spectroscopy and Quadrupole Mass Spectrometer. It is fund that Ar or $O_2$ dilution to $C_{4}F_{8}$ increases F emission intensity and decreases $CF_2$ intensity. However, the ac frequency to the Helmholtz coil decreases the F intensity and thus increases $CF_2$/F ratio. By adjusting the ac frequency, the optimum etch rate and PR to $SiO_2$ selectivity can be obtained in E-lCP.