• Archives of Pharmacal Research
• /
• 제4권2호
• /
• pp.85-90
• /
• 1981

A quantitative GC-MS spectrometric assay was used for the determination of residual N, N-dimethylaniline as a contaminant in commercial penicillin derivatives from various sources. The assay utilizes selective ion focusing to monitor in a GC effluent the molecular ions of DMA generated by electron impact ionization. This method includes dissolution of the sample in alkaline solution, extraction of organic base with cyclohexane and injection into GC-MS with a 3% OV-17 column. Levels of 50 ppb of DMA were easily measured with a coeffecient of varation less than 5 % and recoveries from spiked samples exceeded 97 %. The results of the determinations of DMA in various commercial penicillins were relatively free of this contaminant.

• 산업식품공학
• /
• 제13권4호
• /
• pp.282-288
• /
• 2009

A dark brownish pigment from fruit body of Auricularia auricula was isolated and characterized in this report. The pigment was obtained with a yield of 0.61%(w/w) by alkaline extraction and subsequent purification steps. It showed the positive $FeCl_3$ test which was the indication of phenolic compounds. A synthetic melanin showed a similar spectrometric characteristics to the pigment extract regarding a characteristic UV absorption between 200-250 nm and infrared absorptions profiles in the finger print region including absorption peaks at 1701 and 1624 $cm^{-1}$. Its element analysis indicated that its atomic copmposition is close to that of DOPA melanin (eumelanin). With the result of its antioxidant activity in the TNBT (5-thio-2-nitrobenzoic acid) assay, we concluded that the dark brownish pigment from A. auricula is a melanin-like compound having a powerful antioxidative activity.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
• /
• pp.395.2-395.2
• /
• 2002

The determination method for 11 corticosteroids (betamethasone, cortisol. cortisone, cortisone acetate. dexamethasone. cortisol acetate, isoflupredone acetate, methylprednisolone. prednisone, prednisolone, and triamcinolone acetonide) in a herbal medicinal preparation (Sibjeondaibotang) by a gas chromatography-mass spectrometric (GC-MS) method with selected ion monitoring (SIM) mode is described. Samples (4 mL) were extracted by liquid-liquid extraction with diethyl ether. (omitted)

• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
• /
• pp.224.1-224.1
• /
• 2003

A sensitive and selective liquid chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) was developed for the determination of beraprost in human plasma. Plasma samples were transferred into 96-well OASIS HLB extraction plate using an automated sample handling system and the drugs were eluted with methanol. The eluents were then evaporated and reconstituted with water. All sample transfer and solid-phase extraction (SPE) was automated through the application of both the PerkinElmer MultiPROBE II HT and TOMTEC Quadra 96 workstation. (omitted)

• Nuclear Engineering and Technology
• /
• 제53권5호
• /
• pp.1642-1651
• /
• 2021

In this study, isophtalic neopentyl glycol polyester (NPG-PES) based composites with different loading ratios of pure tungsten metal (W), tungsten (VI) oxide (WO₃), tungsten boron (WB) and tungsten carbide (WC) composites were prepared as alternative shielding materials for ionizing electromagnetic radiation (IEMR) shielding. Structural characterizations of the composites were done. Gamma spectrometric analysis of composites for 80-2000 keV energy range was performed and their usability as IEMR shielding was discussed. As a result, the produced composites showed a shielding performance of 60-100% of the lead (the most widely used IEMR shielding material) depending on the reinforcement material, reinforcement loading rate and experimental conditions. Thus, it was reported that produced composites could be an alternative to lead shieldings that have several disadvantages as toxic properties, difficulty of processing and inelasticity.

• Bulletin of the Korean Chemical Society
• /
• 제35권5호
• /
• pp.1409-1412
• /
• 2014

Sex hormones are important metabolites in vertebrates' development and reproduction. For rapid screening sex hormones, matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is one of the promising analytical platforms, but MALDI MS faces many challenges in detecting steroids such as low ionization efficiency and matrix background interference. One potential strategy to overcome matrix interference in the low m/z region is using a cyclodextrin (CD)-supported matrix for steroid analysis since CD-supported matrixes are known to effectively suppress matrix-related ion signals. In this study, we aimed to find the optimal CD-supported matrix for the analysis of the nonderivatized sex steroids. Our results showed that the ${\alpha}CD$-supported 2,5-dihydroxybenzoic acid (DHB) matrix efficiently ionized all three major classes of sex hormones, estrogens, androgens, and progestagens, with low or no matrix background and also with high sensitivity. In addition, the ${\alpha}CD$-supported DHB matrix mainly generated molecular ions or protonated ions of sex hormones, and this enabled us to obtain information-rich tandem mass spectra which potentially lead to unambiguous identification of steroid species from complex metabolite mixtures.

• Journal of Microbiology and Biotechnology
• /
• 제16권11호
• /
• pp.1740-1746
• /
• 2006

Enrichment techniques led to the isolation of a Pseudomonas sp. strain P2 from municipal waste-contaminated soil sample, which could utilize different isomers of a commercial mixture of 4-nonylphenol when grown in the presence of phenol. The isolate was identified as Pseudomonas sp., based on the morphological, nutritional, and biochemical characteristics and 16S rDNA sequence analysis. The ${\beta}$-ketoadipate pathway was found to be involved in the degradation of phenol by Pseudomonas sp. strain P2. Gas chromatography-mass spectrometric analysis of the culture media indicated degradation of various major isomers of 4-nonylphenol in the range of 29-50%. However, the selected ion monitoring mode of analysis of biodegraded products of 4-nonylphenol indicated the absence of any aromatic compounds other than those of the isomers of 4-nonylphenol. Moreover, Pseudomonas sp. strain P2 was incapable of utilizing various alkanes individually as sole carbon source, whereas the degradation of 4-nonylphenol was observed only when the test organism was induced with phenol, suggesting that the degradation of 4-nonylphenol was possibly initiated from the phenolic moiety of the molecule, but not from the alkyl side-chain.

• 대한화학회지
• /
• 제38권10호
• /
• pp.726-733
• /
• 1994

대기부유분진(air particulate material)중에 존재하는 다환방향족탄화수소(polycyclic aromatic hydrocarbons, PAH)를 신속하고 정확하게 분석하기 위하여 대기부유분진 시료를 10ml의 초임계유체($N_2O$ )로 30분간 추출 후 별도의 전처리와 농축과정 없이 GC/MS에서 분석하여 분석시간과 분석과정을 단축 및 단순화하였다. 시료로서 NBS 대기부유분진 인증표준기준물질(certified particulate reference material, CRM)1649와 서울의 도심에서 채취한 대기부유분진 시료를 이용하여 기존의 추출법 및 분석방법과 비교하였다. 그 결과 본 분석방법은 기존의 분석법에 비해 회수율은 상대적으로 작았으나 재현성이 좋았으며 분석과정이 간단하고 분석시간이 현저히 단축됨을 알 수 있었다.

• 미생물학회지
• /
• 제54권1호
• /
• pp.46-52
• /
• 2018

다환 방향족 탄화수소(polycyclic aromatic hydrocarbon, PAH) 우수 분해균주인 Novosphingobium pentaromativorans US6-1의 dibenzofuran (DBF) 분해경로를 밝히기 위하여 중간대사물질 분석과 전사체 분석을 진행하였다. GC/MS로 중간대사물질을 분석한 결과, 3(2H)-벤조퓨라논이 검출되었는데 이 화합물은 측면 이산소화에 의해 생성된 중간대사산물들의 기본 골격이 되는 물질로써 균주 US6-1에 의한 DBF의 분해가 측면 이산소화로 진행될 가능성을 시사한다. RNA-Seq 분석 결과, 균주 US6-1이 DBF에 노출되었을 때 발현되는 유전자들의 대부분이 lateral dioxygenation과 관련이 있다는 것을 확인하였다. 이상의 결과로부터N. pentaromativorans US6-1에 의해 일어나는 측면 이산소화를통한 DBF 분해경로와 관련 유전자들을 제시하였다.

• 한국식품과학회지
• /
• 제26권5호
• /
• pp.649-654
• /
• 1994

증류주의 pH는 $3.43{\sim}5.85$ 범위였으며 안동소주, 이강주, 마오타이츄, 문배술, 옛향-보리 등은 약 pH4.00이하 이었다. 총산은 마오타이츄가 매우 높았으며 일본의 센바타누키, 중국산 빠이걸, 북한산 백로술은 매우 낮은 값을 보였다. 우리나라 민속소주의 총산은 $11{\sim}88\;mg/100ml$였다. 첨가물이 있는 백로술, 빠이걸, 츄우예칭츄, 이강주의 전기전도도값이 매우 크게 나타났으며 증류주의 밀도는 $0.9121{\sim}1.0833\;g/ml$ 범위였고 백로술이 특이하게 1.0000 g/ml보다 높은 값을 보여 주었다. 증류주의 굴절률은 $1.3263{\sim}1.3610$ 범위였다. 우리나라 전통민속주들은 $274{\sim}278\;nm$ 부근에서 자외부 흡수극대를 나타내었고 스카치위스키, 진도홍주, 마오타이츄, 츄우예칭츄등 착색된 증류주는 넓은 파장 범위에서 강한 자외부흡수를 나타내었다. 물리화학적 특성값보다는 흡광도 자료에 대한 주성분 분석이 우리나라 민속소주와 중국산 카오리양츄를 서로 다른 집락으로 잘 나타내었다. 이러한 결과를 통하여 증류주의 품질관리, 분류동정, 유사성과 이질성 파악에 유익한 정보를 얻을 수 있었다.