• Bulletin of the Korean Chemical Society
• /
• 제30권2호
• /
• pp.368-372
• /
• 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.

• 대한본초학회지
• /
• 제22권2호
• /
• pp.97-102
• /
• 2007

Objectives : This study presents a high performance liquid chromatography - electrospray ionization-mass spectrometer (HPLC-MS/MS) methods for the quantitative and qualitative analysis of various active components in Samul-tang, which is composed of four crude herbs. Methods : HPLC-ESI-MS/MS for the determinations of paeoniflorin and 5-HMF (5-hydroxymethyl 2-furaldehyde) in the Samul-tang, the separation method was performed on an COSMOS1L 5C18-AR-Il (2.0 X 150 mm I.D.) column by gradient elution with 0.1% acetic acid and 5% CH3CN in water (A)-0.1% acetic acid and 5% H20 in CH3CN (B) as the mobile phase at a flow-rate of 300 ${\mu}L/min$ with detection at quadrupole mass spectrometer. The all marker substances were always detected as the base peaks in the positive ion mode. Results : The paeoniflorin of Paeoniae Radix in Samul-tang showed a strong base peak [M+H2O]+ in the positive detection mode to give the following as; paeoniflorin (498.109 [M+H2O]+, 479.8 [M]+, 301 [M-glucose]+, 179.3 [glucose]+). Based on the HPLC retnetion time and MS of standard compounds confirmed the identity of active compounds in Rehmanniae Radix Preparata as follows; 5-HMF (127.0[M+H]+, 109.3 [M-OH]+) in the positive ion mode. Conclusion : According to the above results, HPLC-ESI-MS method permits assignment of tentative structures such as paeoniflorin and 5-HMF in the Samul-tang.

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2020년도 추계학술대회
• /
• pp.157-157
• /
• 2020

• 한국작물학회:학술대회논문집
• /
• 한국작물학회 2020년도 춘계학술대회
• /
• pp.183-183
• /
• 2020

• Journal of Microbiology and Biotechnology
• /
• 제13권6호
• /
• pp.859-865
• /
• 2003

Surfactin is a mixture of cyclic lipopeptides built from variants of a heptapeptide and a ${\beta}-hydroxy$ fatty acid produced by several strains of Bacillus sp. Surfactin isoforms produced by endophytic Bacillus sp. CY22 from a balloon flower were isolated and characterized. It was found that the purified surfactin had three isoforms with protonated masses of m/z 1,008, 1,022, and 1,036, and different structures in combination with Na, K, Ca ions using MALDI-TOF MS, ESI-MS/MS, and ICP MS, respectively. In the MS/MS analysis, the isolated surfactin had the identical amino acid sequence (LLVDLL) and hydroxy fatty acids (with 13 to 15 carbons in length), even though isolated from different Bacillus strains. The sfp22 gene, required for producing the surfactin, consisted of an open reading frame (ORF) of 675 bp encoding 224 amino acid residues with a signal peptide of 20 amino acids. The predicted amino acid sequence of sfp22 was very similar to that of Ipa-8.

• Bulletin of the Korean Chemical Society
• /
• 제28권5호
• /
• pp.737-744
• /
• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of acrylamide in potato chips, starch-rich foodstuff cooked at high temperature. Sample was spiked with 13C3-acrylamide and then extracted with water. The extract was further cleaned up with an Oasis HLB solid-phase extraction (SPE) cartridge and an Oasis mixed-phase cation exchange (MCX) SPE cartridge. The extract was analyzed by using LC/ESI/Tandem MS in positive ion mode. LC with a medium reversed-phase (C4) column was optimized to obtain adequate chromatographic retention and separation of acrylamide. MS was operated to selectively monitor [M+H]+ ions of the analyte and its isotope analogue at m/z 72 and m/z 75, respectively. Sample was also analyzed by the LC/MS with selectively monitoring the collisionally induced dissociation channels of m/z 72 → m/z 55 and m/z 75 → 58. Compared to the LC/MS chromatograms, the LC/MS/MS chromatograms showed substantially reduced background chemical noises coming from solvent clusters formed during ESI spray processes and interferences from sample matrix. Repeatability and reproducibility studies showed that the LC/MS/MS method is a reliable and reproducible method which can provide a typical method precision of 1.0% while the LC/MS results are influenced by chemical interferences.

• Journal of Microbiology and Biotechnology
• /
• 제14권3호
• /
• pp.620-627
• /
• 2004

On the foundation of a database of genome sequences and protein analyses, the ability to clone a gene based on a peptide analysis is becoming more feasible and effective for identifying a specific gene and its protein product of interest. As such, the current study conducted a protein analysis using 2-D PAGE followed by MALDI- TOF and ESI-MS to identify a highly expressed gene product of C. parasitica. A distinctive and highly expressed protein spot with a molecular size of 47.2 kDa was randomly selected and MALDI-TOF MS analysis was conducted. A homology search indicated that the protein appeared to be a fungal enolase (enol). Meanwhile, multiple alignments of fungal enolases revealed a conserved amino acid sequence, from which degenerated primers were designed. A screening of the genomic $\lambda$ library of C. parasitica, using the PCR amplicon as a probe, was conducted to obtain the full-length gene, while RT-PCR was performed for the cDNA. The E. coli-expressed eno 1 exhibited enolase enzymatic activity, indicating that the cloned gene encoded the C. parasitica enolase. Moreover, ESI-MS of two of the separated peptides resolved from the protein spot on 2-D PAGE revealed sequences identical to the deduced sequences, suggesting that the cloned gene indeed encoded the resolved protein spot. Northern blot analysis indicated a consistent accumulation of an eno1 transcript during the cultivation.

• 약학회지
• /
• 제51권2호
• /
• pp.96-102
• /
• 2007

Measurement of globotriaosylceramide (Gb3, ceramide trihexoside) in urine has clinical importance for monitoring after enzyme replacement therapy in Fabry disease patients. The disease is an X-linked lipid storage disorder that results from a deficiency of the enzyme ${\alpha}$-galactosidase A (${\alpha}$-Gal A). The lack of ${\alpha}$-Gal A causes an intracellular accumulation of glycosphingolipids, mainly Gb3. A simple, rapid, and highly sensitive analytical method for Gb3 in urine was developed without labor-extensive pre-treatment by electrospray ionization MS/MS (ESI-MS/MS). Only simple 5-fold dilution of urine is necessary for the extraction and isolation of Gb3 in urine. Gb3 in diluted urine was dissolved in dioxane containing C17:0 Gb3 as an internal standard. After centrifugation it was directly injected and analyzed through guard column by in combination with multiple reaction monitoring mode of ESI-MS/MS. Eight isoforms of Gb3 were completely resolved from urine matrix. C24:0 Gb3 occupied 50% of total Gb3 as a major component in urine. Linear relationship for Gb3 isoforms was found in the range of 0.005${\sim}$5.0 ${\mu}$g/ml. The limit of detection (S/N=5) was 0.005 ${\mu}$g/ml and limit of quantification was 0.05 ${\mu}$g/ml for C24:0 Gb3 with acceptable precision and accuracy. Correlation coefficient of calibration curves for 8 Gb3 isoforms ranged from 0.9598 to 0.9975. This method could be useful for rapid and sensitive 1st line Fabry disease screening, monitoring and/or diagnostic tool for Fabry disease.

• 분석과학
• /
• 제22권4호
• /
• pp.326-335
• /
• 2009

계란 중에 잔류하는 6 종의 글루코코티코이드 약물을 극미량으로 분석하는 방법이 개발되었다. 동시분석을 위한 시료 추출방법과 정제방법을 확립하였으며 액체 크로마토그래프와 질량분석기의 최적화 조건을 확립하였으며, 글루코코티코이드를 분석하기 위해서는 5 g의 계란에 초산 완충용액을 사용하여 시료의 pH를 5.2로 조절한 후 효소 가수분해를 위해 Helilx pomatia를 사용하였다. 혼합물을 원심분리하여 20 mL n-헥산으로 두 번 추출하였다. 다시 HLB 카트리지에서 메탄올에 의한 추출이 이루어진 후 연속해서 실리카 카트리지에서 메탄올/에틸아세테이트를 사용하여 정제하였다. 분석물질은 역상 HPLC/ESI-MS/MS로 분석하였으며 ESI는 음이온 모드를 사용하였다. 검정곡선의 상관계수는 0.99 이상을 나타내었고 검출한계는 $0.09-0.17{\mu}g/kg$ 이었으며 회수율은 55.7-69.8%이었다. 바탕 계란 중에서 실험된 유효성 검증방법에 근거하여 확립된 분석법은 계란 중 글루코코티코이드를 수 ${\mu}g/kg$ 농도까지 검출하는데 사용될 수 있을 것이다.

• Bulletin of the Korean Chemical Society
• /
• 제34권9호
• /
• pp.2663-2670
• /
• 2013

The purpose of stability testing is to provide evidence about how the quality of a drug varies with time under the influence of a variety of environmental factors. In this study, erythropoietin (EPO) was analyzed under different pH (pH 3 and pH 9) and temperature ($25^{\circ}C$ and $40^{\circ}C$) conditions according to current Good Manufacturing Practice (cGMP) and International Conference on Harmonisation (ICH) guidelines. The molecular weight difference between intact EPO and deglycosylated EPO was determined by SDS-PAGE, and aggregated forms of EPO under thermal stress and high-pH conditions were investigated by size exclusion chromatography. High pH and high temperature induced increases in dimer and high molecular weight aggregate forms of EPO. UPLC-ESI-TOF-MS was applied to analyze the changed modification sites on EPO. Further, normal-phase high-performance liquid chromatography was performed to identify proposed glycan structures and high pH anion exchange chromatography was carried out to investigate any change in carbohydrate composition. The results demonstrated that there were no changes in modification sites or the glycan structure under severe conditions; however, the number of dimers and aggregates increased at $40^{\circ}C$ and pH 9, respectively.