• Mass Spectrometry Letters
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• v.6 no.1
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• pp.13-16
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• 2015

This study demonstrated the stabilizing role of a cyclodextrin on Keggin $[PW_{12}O_{40}]^{3-}$ via hydrogen bonding complexation unveiled by ESI-MS. The distinctive fragmentation pathways of the $\{PW_{12}\}/{\gamma}$-CD complexes from that of discrete $[PW_{12}O_{40}]^{3-}$ showed that the so-called "weak" non-covalent interactions can effectively change the dissociation chemistry of POM in the gas phase. The influence of different types of solvents and organic additives such as ${\gamma}$-CD on the stability of Keggin $[PW_{12}O_{40}]^{3-}$ was also addressed firstly by ESI-MS.

• Journal of Environmental Science International
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• v.24 no.12
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• pp.1569-1582
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• 2015

The analytical method for 16 organophosphorus pesticides was developed in this study. The 16 organophosphorus pesticides were analyzed by liquid chromatography-tandem mass spectrometry (LC/MS/MS) using on-line solid phase extraction (on-line SPE) with PLRP- S cartridge. Analysis of all analytes in the MS/MS was processed in the electrospray ioni-zation (ESI) positive mode. They are Azinphos ethyl, Chlorfenvinphos, Ethion, Famphur, Phosmet, Phosphamidon, Terbufos, Aspon, Chlorpyrifos-methyl, Crotoxyphos, Dichlofenthi-on, Dicrotophos, Fonofos, Thionazin, Dimethoate and Iprobenfos. Limits of detection (LODs) and Limits of quantification(LOQs) were obtained as 0.8~2.0 ng/L and 2.6~6.4 ng/L, respectively. All compounds were not detected at the 8 sampling points of the raw water and clean water.

• YAKHAK HOEJI
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• v.55 no.1
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• pp.56-63
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• 2011

Fabry disease (FD) is an X-linked inborn error of glycoshpingolipid metabolism resulting from mutation in the enzyme ${\alpha}$-galactosidase A gene. The disease is an X-linked lipid storage disorder and the lack of ${\alpha}$-Gal A causes an intracellular accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb-3). Measurement of Gb-3 in plasma has clinical importance for monitoring after enzyme replacement therapy for confirmed FD patients. Using electrospray ionization MS/MS we had developed, a simple, rapid, and highly sensitive analytical method for Gb-3 in plasma was used for the purpose of screening FD among high risk groups in Korean population. To date, no comprehensive results for FD screening have been performed and reported in Korea. We screened 1,100 outpatients from 13 hospitals (including clinics) to assess the incidence of FD among patients in high risk groups. For patients with borderline level amount of Gb-3, we repeated Gb-3 or performing complementary or confirmative assay with ${\alpha}$-Gal A activity and DNA mutaion analysis for confirmation diagnosis. Of 1,100 we diagnosed 3 FD with 2 classical type and 1 carrier (0.27%).

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.368-372
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• 2009

The trace polymer and additives in used stripper solutions were analyzed by a combination of Py-GC/MS and ESI-MS. In the comparison of the pyrolysates produced by the pyrolysis of the pure stripper and photoresist at $500{^{\circ}C}$, the presence of novolac polymer in the used stripper was confirmed by the presence of the characteristic peaks of its pyrolysates, such as those of the methylphenol, di-methylphenol and methylenebis(methylphenol) isomers. The intact trace polymer was measured by ESI-MS, which showed the distribution of oligomers at intervals of 120 Da, indicating di-methylphenol to be the repeat unit. Additional MS/MS measurements demonstrated that the end group is methylphenol and the repeat groups are di-methylphenol. Some modified oligomers caused by the methylation or di-methylation of the repeat unit were also identified. Although the polymer is only present at a trace level in the used stripper, these combined analytical methods provided the means to qualify the stripper solution through the identification and structural determination of the polymer.

• Mass Spectrometry Letters
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• v.8 no.2
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• pp.29-33
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• 2017

Understanding the mechanisms that control and concentrate the observed electrospray ionisation (ESI) response from peptides is important. Controlling these mechanisms can improve signal-to-noise ratio in the mass spectrum, and enhances the generation of intact ions, and thus, improves the detection of peptides when analysing mixtures. The effects of different mixtures of aqueous: organic solvents (25, 50, 75%; v/v): formic acid solution (at pH 3.26) compositions on the ESI response and charge-state distribution (CSD) during mass spectrometry (MS) were determined in a group of biologically active peptides (molecular wt range 1.3 - 3.3 kDa). The ESI response is dependent on type of organic solvent in the mobile phase mixture and therefore, solvent choice affects optimal ion intensities. As expected, intact peptide ions gave a more intense ESI signal in polar protic solvent mixtures than in the low polarity solvent. However, for four out of the five analysed peptides, neither the ESI response nor the CSD were affected by the volatility of the solvent mixture. Therefore, in solvent mixtures, as the composition changes during the evaporation processes, the $pK_b$ of the amino acid composition is a better predictor of multiple charging of the peptides.

• Journal of Food Hygiene and Safety
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• v.32 no.2
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• pp.89-95
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• 2017

A rapid, sensitive analytical method for glucuronolactone in beverages was developed and validated using hydrophilic interaction liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HILIC-ESI-MS/MS). To determine the optimum analytical conditions for glucuronolactone, three different kinds of HILIC columns and two mobile phases with different pH values were examined. An amide-bonded stationary phase with a pH 9 acetonitrile-rich mobile phase was the best condition in terms of column retention, ESI-MS/MS response area, and signal-to-noise ratio. After extraction, glucuronolactone was separated through the HILIC amide column and detected by negative ESI-MS/MS in selected reaction monitoring (SRM) mode. Nine energy drinks sold in Korea were spiked with glucuronolactone at a concentration of 5 ng/mL; the Monster $Energy^{TM}$ sample showed the smallest peak area and its signal-to-noise ratio was used for method validation. Good linearity was obtained in the concentration range from 20 to 1500 ng/mL with a correlation coefficient > 0.998. The developed method had a limit of detection (LOD) of 6 ng/mL and a limit of quantitation (LOQ) of 20 ng/mL. The recovery of this method at concentration of 20, 100, 500, and 1000 ng/mL was 96.3%-99.2% with relative standard deviations (RSD) of 1.6%-14.0%. A reproducibility precision assessment at concentration of 100 and 500 ng/mL was carried out among three laboratories. The recovery of that evaluation was 95.1%-102.3% with RSD of 2.7%-7.0%. An analysis of variance indicated that there was no difference between the recovery results of the three laboratories at the 5% significance level. The validated method is applicable to inspecting beverages adulterated with glucuronolactone in Korea.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.25-31
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• 2006

Changes of CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) in the glyphosate-tolerant Roundup Ready soybean were examined using purified CP4 EPSPS produced in cloned Escherichia coli as a control. CP4 EPSPS in genetically modified soybean was detected by twodimensional gel electrophoresis (2-DE) and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and electrospray ionization tandem mass spectrometry (ESI-MS/MS) with databases. CP4 EPSPS in soybean products was resolved on 2-DE by first isoelectric focusing (IEF) based on its characteristic pI of 5.1, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) based on its molecular mass of 47.5 kDa. We quantified various percentages of soybean CP4 EPSPS. The quantitative analysis was performed using a 2D software program on artificial gels with spots varying in Gaussian volumes. These results suggested that 2-DE image analysis could be used for quantitative detection of GM soybean, unlike Western blotting.

• Journal of Korean Neurosurgical Society
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• v.48 no.1
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• pp.8-13
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• 2010

Objective : The etiology and pathogenesis of moyamoya disease remain unclear. Furthermore, the definitive diagnostic protein-biomarkers for moyamoya disease are still unknown. The present study analyzed serum proteomes from normal controls and moyamoya patients to identify novel serological biomarkers for diagnosing moyamoya disease. Methods : We compared the two-dimensional electrophoresis patterns of sera from moyamoya disease patients and normal controls and identified the differentially-expressed spots by matrix-assisted laser desorption/ionization-time-of flight mass spectrometry and electrospray ionization quadruple time-of-flight mass spectrometry. Results : We found and analyzed 22 differently-expressed proteomes. Two proteins were up-regulated. Twenty proteins were down-regulated. Complement C1 inhibitor protein and apolipoprotein C-III showed predominantly changed expressions (complement C1 inhibitor protein averaged a 7.23-fold expression in moyamoya patients as compared to controls, while apolipoprotein C-III averaged a 0.066-fold expression). Conclusion : Although our study had a small sample size, our proteomic data provide serologic clue proteins for understanding moyamoya disease.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.124-131
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• 2016

Among 116 bacterial strains isolated from Korean fermented foods, one strain (SS-76) was selected for producing new oligosaccharides in a basal medium containing maltose as the sole source of carbon. Upon morphological characterization using scanning electron microscopy, the cells of strain SS-76 appeared rod-shaped; subsequent 16S rRNA gene sequence analysis revealed that strain SS-76 was phylogenetically close to Bacillus subtilis. The main oligosaccharide fraction B extracted from the culture supernatant of B. subtilis SS-76 was purified by high performance liquid chromatography. Subsequent structural analysis revealed that this oligosaccharide consisted only of glucose, and methylation analysis indicated similar proportions of glucopyranosides in the 6-linkage, 4-linkage, and non-reducing terminal positions. Matrix-assisted laser-induced/ionization time-of-flight/mass spectrometry and electrospray ionization-based liquid chromatography-mass spectrometry/mass spectrometry analyses suggested that this oligosaccharide consisted of a trisaccharide unit with 1,6- and 1,4-glycosidic linkages. The anomeric signals in the $^1H$-nuclear magnetic resonance spectrum corresponded to ${\alpha}$-anomeric configurations, and the trisaccharide was finally identified as panose (${\alpha}$-D-glucopyranosyl-1,6-${\alpha}$-D-glucopyranosyl-1,4-D-glucose). These results suggest that B. subtilis SS-76 converts maltose into panose; strain SS-76 may thus find industrial application in the production of panose.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.519-525
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• 2009

A bacterial strain (Strain N-08) capable of extracellularly producing high level of non-reducing oligosaccharide (NR-OS) isolated from soil. The strain was identified phylogenetically by 16S rDNA sequence analysis and found to be very close to Arthrobacter crystallopoietes. The high production of NR-OS was observed in the basal culture medium containing maltose as a sole carbon source. The NR-OS in culture supernatant was purified by glucoamylase treatment and Dowex-1 (OH.) ion exchange chromatography and its structure was characterized. This oligosaccharide consisted of only glucose. Methylation analysis indicated that this fraction was composed mainly of non-reducing terminal glucopyranoside. Matrixassisted laser-induced/ionization time-of-flight (MALDI-TOF) and electrospray ionization-mass spectrometry (ESI-MS)/MS analyses suggested that this oligosaccharide comprised non-reducing disaccharide unit with 1,1-glucosidic linkage. When this disaccharide was analyzed by $^1H$-NMR and $^{13}C$-NMR, it gave the same signals with $\alpha$-D-glucopyranosyl-(1,1)-$\alpha$-Dglucopyranoside. These results indicated that the NR-OS produced by A. crystallopoietes N-08 was ${\alpha}1$,${\alpha}1$-trehalose. This is the first report of the trehalose which can be produced directly from maltose by A. crystallopoietes N-08.