http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Microwave-assisted Weak Acid Hydrolysis of Proteins
( Miyeong Seo ),( Jinhee Kim ),( Sehwan Park ),( Ji-hye Lee ),( Taehee Kim ),( Jihyeon Lee ),( Jeongkwon Kim ) 한국질량분석학회 2012 Mass spectrometry letters Vol.3 No.2
Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at 37 oC, 50 oC, and 100 oC for 1 h. The most effective hydrolysis was observed at 100 oC. Hydrolysis products were investigated using matrixassisted laser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini of aspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60- min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at 100 oC. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteins and that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.
Seo, Miyeong,Kim, Byungjoo,Baek, Song-Yee Springer-Verlag 2015 Analytical and Bioanalytical Chemistry Vol.407 No.18
<P>Patulin, a mycotoxin produced by several molds in fruits, has been frequently detected in apple products. Therefore, regulatory bodies have established recommended maximum permitted patulin concentrations for each type of apple product. Although several analytical methods have been adopted to determine patulin in food, quality control of patulin analysis is not easy, as reliable certified reference materials (CRMs) are not available. In this study, as a part of a project for developing CRMs for patulin analysis, we developed isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC/MS/MS) as a higher-order reference method for the accurate value-assignment of CRMs. (13)C7-patulin was used as internal standard. Samples were extracted with ethyl acetate to improve recovery. For further sample cleanup with solid-phase extraction (SPE), the HLB SPE cartridge was chosen after comparing with several other types of SPE cartridges. High-performance liquid chromatography was performed on a multimode column for proper retention and separation of highly polar and water-soluble patulin from sample interferences. Sample extracts were analyzed by LC/MS/MS with electrospray ionization in negative ion mode with selected reaction monitoring of patulin and (13)C7-patulin at m/z 153m/z 109 and m/z 160m/z 115, respectively. The validity of the method was tested by measuring gravimetrically fortified samples of various apple products. In addition, the repeatability and the reproducibility of the method were tested to evaluate the performance of the method. The method was shown to provide accurate measurements in the 3-40 μg/kg range with a relative expanded uncertainty of around 1%.</P>
Joongwon Lee,Seik Park,Haikyung Seo,Miyeong Kim,Simoon Kim,Junhwa Chi,Kitae Kim 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.5
The integrated gasification combined cycle (IGCC) system is well known for its high efficiency compared with that of other coal fueled power generating systems. In this study, gasification using different types of burners with different oxygen supply angles in a bench-scale entrained flow gasifier was investigated. The effects of the oxygen gas supply angle of the coal burner and resulting oxygen supply location in the gasifier on the syngas composition and temperature of the gasifier were experimentally examined. These changes had a significant influence on the syngas composition of the final stream, carbon conversion, and efficiencies. According to the experimental results, the models using the Aspen Plus process simulator were positioned to define the effects of the experimental parameters and to find the optimum operating conditions in the bench gasifier facility.