• Mass Spectrometry Letters
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• 제12권4호
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• pp.192-199
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• 2021

Alpine glaciers harbor a large quantity of bio-labile dissolved organic matter (DOM), which plays a pivotal role in global carbon cycling as glacial-fed streams are headwaters of numerous large rivers. To understand the complexity, origin, and fate of DOM in glaciers and downstream-linked streams and lakes, we elucidated the molecular composition of DOM in two different Tibetan Plateau glaciers, eight glacial-fed streams and five lakes, using an ultrahigh-resolution 15 Tesla Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The compositional changes of the DOM samples revealed that glacier DOM mostly exhibited sulfur-containing organic compounds (CHOS species). We also found that aliphatic formulae contributed more than 50% of the total abundance of assigned molecules in glacier samples, and those compounds were significantly related to CHOS species. The CHO proportions of glacial-fed streams and lakes samples increased with increasing distance from glacial terminals. The relative contribution of terrestrial-derived organics (i.e., lignins and tannins) declined while microbial-originated organics (aliphatics) increased with increasing elevation. This suggested the gradual input of allochthonous materials from non-glacial environment and the degradation of microbe-derived compounds along lower elevations. Alpine glaciers are retreating as a result of climate change and they nourished numerous streams, rivers, and downstream-linked lakes. Therefore, the interpretations of the detailed molecular changes in glacier ice, glacial-fed streams, and alpine lakes on the Tibetan Plateau could provide broad insights for understanding the biogeochemical cycling of glacial DOM and assessing how the nature of DOM impacts fluvial ecosystems.

• Mass Spectrometry Letters
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• 제4권4호
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• pp.75-78
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• 2013

A gas chromatography/mass spectrometric (GC/MS) method was developed as a candidate reference method for the accurate determination of essential fatty acids (linoleic acid, ${\alpha}$- and ${\gamma}$-linolenic acids) in food supplemental oil products. Samples were spiked with three internal standards (stearic acid-$d_{35}$, $^{13}C_{18}$-linoleic acid, and $^{13}C_{18}$-${\alpha}$-linolenic acid). Samples were then subject to saponification, derivatization for methylation, and extraction by organic solvent. For GC/MS measurement, an Agilent HP-88 column, designed for the separation of fatty acid methyl esters, was selected after comparing with other columns as it provided better separation for target analytes. Target analytes and internal standards were detected by selected ion monitoring of molecular ions of their methyl ester forms. The GC/MS method was applied for the measurement of three botanical oils in NIST SRM 3274 (borage oil, evening primrose oil, and flax oil), and measurement results agreed with the certified values. Measurement results for target analytes which have corresponding isotope-labeled analogues as internal standard were calculated based on isotope dilution mass spectrometry (IDMS) approach, and compared with results calculated by using the other two internal standards. Results from the IDMS approach and the typical internal standard approach were in good agreement within their measurement uncertainties. It proves that the developed GC/MS method can provide similar metrological quality with IDMS methods for the measurement of fatty acids in natural oil samples if a proper fatty acid is used as an internal standard.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.212-217
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• 2005

Desorption/ionization on silicon mass spectrometry (DIOS-MS) is a relatively new laser desorption/ionization technique for mass spectrometry without employing an organic matrix. This present study was carried to survey the experimental factors to improve the efficiency of DIOS-MS through electrochemical etching condition in structure and morphological properties of the porous silicon. The porous structure of silicon structure and its properties are crucial for the better performance of DIOS-MS and they can be controlled by the suitable selection of electrochemical conditions. The fabrication of porous silicon and ion signals on DIOS-MS were examined as a function of silicon orientation, etching time, etchant, current flux, irradiation, pore size, and pore depth. We have also examined the effect of pre- and post-etching conditions for their effect on DIOS-MS. Finally, we could optimize the electrochemical conditions for the efficient performance of DIOS-MS in the analysis of small molecule such as amino acid, drug and peptides without any unknown noise or fragmentation.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.231-236
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• 2006

A novel sample pretreatment technique, headspace hanging drop liquid phase microextraction (HS-LPME) was studied and applied to the determination of flavors from solid clove buds by gas chromatography-mass spectrometry (GC-MS). Several parameters affecting on HS-LPME such as organic solvent drop volume, extraction time, extraction temperature and phase ratio were investigated. 1-Octanol was selected as the extracting solvent, drop size was fixed to 0.6 $\mu$L. 60 min extraction time at 25 ${^{\circ}C}$ was chosen. HS-LPME has the good efficiency demonstrated by the higher partition equilibrium constant ($K_{lh}$) values and concentration factor (CF) values. The limits of detection (LOD) were 1.5-3.2 ng. The amounts of eugenol, $\beta$-caryophyllene and eugenol acetate from the clove bud sample were 1.90 mg/g, 1.47 mg/g and 7.0 mg/g, respectively. This hanging drop based method is a simple, fast and easy sample enrichment technique using minimal solvent. HSLPME is an alternative sample preparation method for the analysis of volatile aroma compounds by GC-MS.

• 대한유전성대사질환학회지
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• 제18권1호
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• pp.1-12
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• 2018

목적: 유기산 대사이상 질환은 신경학적 증상과 증후를 포함하여 다양한 임상증상으로 나타날 수 있으며 때로는 생명을 위협할 수 있는 급성 악화로 발현될 수 있다. 따라서 이환된 환자들의 예후는 조기 진단과 치료에 의해 좌우된다. 탠덤매스검사의 도입 후 본원에 의뢰된 검체들을 분석하여 유기산 대사이상 질환의 진단율의 변화 및 연령별 분포와 임상양상을 알아보기 위해 본 연구를 시행하였다. 방법: 2007년 1월부터 2015년 9월까지 약 8년 9개월간 전국에 있는 대학병원에서 의뢰된 2,794례의 검체들을 이용하여 소변 유기산검사를 실시하였고 임상증상과 성별 및 연령군별 분포를 분석하여 정리하였다. 불확실한 결과를 보였던 환자들은 24시간 이상의 고단백 식사 후와 24시간 이상의 단백질 제한식사 후에 소변 유기산 분석을 재시행 하였다. 결과: 총 20가지 질환, 626례의 환자들이 진단되었는데, 사립체 질환이 482례로 가장 많이 진단되었고 그 뒤를 이어 케톤분해이상질환군 67례, 3-히드록시이소부티르산뇨증 32례, EPEMA 증후군 8례, 3-메틸크로토닐 글리신뇨증 7례, 글루타르산뇨증 II형 6례와 I형 4례, 메틸말론산뇨증, 이소발레린산뇨증, 중쇄 acyl-CoA 탈수소효소 결핍증이 각 3례 등이 진단되었다. 결론: 탠덤매스를 이용한 신생아 선별검사가 점차 보편화되고 의료환경의 변화로 인해, 이전의 보고와 비교했을 때 본 연구 기간동안의 유기산 대사이상 질환의 진단율은 다소 감소하였다. 유기산 대사이상 질환들은 다양한 증상들이 나타나고 종종 생명을 위협하는 상태로 발현되는 경우가 많다. 조기 진단과 처치를 통해 이런 급성 악화의 발현을 예방할 수 있기 때문에 진료현장에서 비특이적인 증상 및 신경학적 장애를 보이는 환자를 진료할 때 주의가 필요하다고 할 수 있겠다.

• 한국환경과학회지
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• 제9권1호
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• pp.89-93
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• 2000

Twenty organic chemical substances(Table 2) were isolated from untreated wastewater, as well as treated wastewater, collected at 76 companys of 9 industry group located in the basin of Youngsan River. Those organic compounds were analyzed by Gas Chromatography/Mass Spectrometry(GC/MS) and confirmed through comparison with each standard reagents. Phenol, which was not detected in the raw wastewater, was identified in the effluent of treatment facility, indicating that phenol is generated from isopropylbenzene of plant wastewater.

• Journal of Ginseng Research
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• 제41권2호
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• pp.195-200
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• 2017

Background: The natural ratios of carbon (C), nitrogen (N), and sulfur (S) stable isotopes can be varied in some specific living organisms owing to various isotopic fractionation processes in nature. Therefore, the analysis of C, N, and S stable isotope ratios in ginseng can provide a feasible method for determining ginseng authenticity depending on the cultivation land and type of fertilizer. Methods: C, N, and S stable isotope composition in 6-yr-old ginseng roots (Jagyeongjong variety) was measured by isotope ratio mass spectrometry. Results: The type of cultivation land and organic fertilizers affected the C, N, and S stable isotope ratio in ginseng (p < 0.05). The ${\delta}^{15}N_{AIR}$ and ${\delta}^{34}S_{VCDT}$ values in ginseng roots more significantly discriminated the cultivation land and type of organic fertilizers in ginseng cultivation than the ${\delta}^{13}C_{VPDB}$ value. The combination of ${\delta}^{13}C_{VPDB}$, ${\delta}^{15}N_{AIR}$, or ${\delta}^{34}S_{VCDT}$ in ginseng, except the combination ${\delta}^{13}C_{VPDB}-^{34}S_{VCDT}$, showed a better discrimination depending on soil type or fertilizer type. Conclusion: This case study provides preliminary results about the variation of C, N, and S isotope composition in ginseng according to the cultivation soil type and organic fertilizer type. Hence, our findings are potentially applicable to evaluate ginseng authenticity depending on cultivation conditions.

• 한국임상수의학회지
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• 제40권6호
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• pp.393-398
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• 2023

We identified mastitis-causing pathogens using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) in an organic dairy farm and evaluated the effects of antimicrobial restriction on antimicrobial susceptibility. A total of 43 Holstein cows without any clinical sign of mastitis were used in this study, and 172 quarter milk samples were cultured on blood agar plates for 24 hours at 37℃. Subsequently, bacterial species were identified and antimicrobial susceptibility tests were performed. The subclinical mastitis infection rates in the cows and quarters were 58.1% (25/43) and 25.6% (44/172), respectively. In the species identification, Staphylococcus aureus (40.9%) was the most prominent isolate, followed by S. chromogenes (22.7%), S. epidermis (18.2%), S. simulans (11.4%), S. haemolyticus (2.3%), S. muscae (2.3%), and S. xylosus (2.3%). In the antimicrobial susceptibility test, all isolates were 100% susceptible to 24 of 28 antibiotics, except for benzylpenicillin, cefalotin, cefpodoxime, and trimethoprim/sulfamethoxazole. The resistance rates of S. aureus, S. chromogenes, and S. muscae isolates to trimethoprim/sulfamethoxazole were 27.8%, 10%, and 100%, respectively, and the resistance rates of S. epidermis and S. xylosus to benzylpenicillin were 50% and 100%, respectively. S. chromogenes, S. epidermis, S. simulans, S. haemolyticus, and S. xylosus were resistant to cefalotin and cefpodoxime. In conclusion, restrictions on antimicrobial use for organic dairy farm certification have resulted in a high Staphylococcus spp. infection rate. Therefore, our study indicates the importance of mastitis management strategies implemented by farmers together with veterinary practitioners, even if mastitis does not appear clinically in organic dairy farms.

• ALGAE
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• 제30권2호
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• pp.171-179
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• 2015

Organic light-emitting materials in marine macrophytes from various coastal environments were identified. Twentyeight species from the solvent fractions were examined and identified as candidates for bioorganic light-emitting materials using photoluminescence (PL) spectra and gas chromatography-mass spectrometry. We selected 16 solvent fractions from a total of 1,221 prepared from Ishige okamurae, Sargassum confusum, Grateloupia elliptica, Chondracanthus intermedius, Porphyra yezoensis, Meristotheca papulosa, Gelidium amansii, and Scytosiphon lomentaria. The maximum light-emitting PL spectra appeared at various colors, mainly between blue and green, based on chromaticity coordinates, from solvent fractions of M. papulosa, G. amansii, G. elliptica, P. yezoensis, S. lomentaria, I. okamurae, and C. intermedius. These results will contribute to the development of novel organic light-emitting materials.

• 분석과학
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• 제8권4호
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• pp.405-410
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• 1995

A study on elemental speciation of trace metals in lake water (Lake Biwa in Japan) has been carried out by a size exclusion chromatography (SEC) / inductively coupled plasma mass spectrometry (ICP-MS) system. Before analysis, the water sample was preconcentrated with a ultrafiltration technique, where the large molecules with molecular weight larger than 10,000 were concentrated. Then the preconcentrated water samples (500-1000 fold) were analyzed by a SEC/ICP-MS system. Most trace metals were found at the UV absorption peaks corresponding to the molecular weights of ca. 300,000 and 10,000-50,000, where trace metals were on-line detected by ICP-MS. The results suggest that many of trace metals exist as the large organic molecules-metal complexes in natural water.