• 공업화학
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• 제10권4호
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• pp.628-634
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• 1999

유기첨가제인 ${\omega}$-phenylalkylammonium 염이 sodium dodecyl sulfate(SDS)의 미셀계면에 결합되는 배향과 미셀속으로 유기염이 침투되는 정도를 $^{1}H\;NMR$ 자료를 이용하여 연구하였다. SDS의 메틸렌 양성자들의 높은장 쪽으로의 화학이동 값의 변화는 유기염의 농도에따라 선형적으로 변하게 되는데 이것은 유기염이 미셀내에 삽입되는 증거이다. 유기염의 알킬기의 길이가 길어질수록 벤젠고리의 양성자들과 계면활성제의 메틸렌 양성자들은 공명 신호들이 더욱 높은장 쪽으로 이동됨을 보여주었다. 유기염들은 알킬암모늄기를 미셀의 계면 밖으로 배향하며 벤젠고리는 미셀의 중심을 향하여 palisade 층까지 침투한다고 생각된다. 유기 첨가제는 알킬기의 길이가 길어질수록 SDS 미셀의 palisade 층으로 더욱 깊이 침투하여 혼합미셀를 형성한다고 생각한다.

• 한국식품영양과학회지
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• 제24권5호
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• pp.702-706
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• 1995

A major component(compound A) in the ethylacetate fraction exhibited a strong antimicrobial activity was identified by UV, IR, FABMS and NMR. The compound A showed strong absorbance at 209, 259 and 359nm, indicating a flavonoid ring structure. IR spectrum possessed absorbance of OH at 3400∼3300cm-1, ketone at around 1650cm-1, and aromatic C=C at around 1660cm-1. Molecular weight of the compound A calculated as 478 from the information of m/z 479(M＋H)+ and m/z 477(M-H)+ in the FABMS spectrum. Molecular formula of this compound was found to be C22H22O12 from m/z 479.1220(＋3.1mmu for C22H23O12) of HRFABMS spectrum and from 13C-NMR spectrum. 1H-NMR and 13C-NMR spectra of the compound A revealed aromatic proton and benzene rings. Distortionless enhancement by polarization transfer(DEPT) exhibited that the compound A possessed 10 quaternary carbons and 3 substituted benzene rings including a methoxy group substitution. The compound A was identified as isorhamnetin 3-O-β-glucopyranoside by spectrophotometric methods in conjunction with 1H-1H COSY, 1H-13C COSY and HMBC, which revealed a flavone with OH group at 3, 5, 7, and 4' and methoxy group at 3' positions esterified to glucose.

• Archives of Pharmacal Research
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• 제20권3호
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• pp.201-205
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• 1997

A very high content (at least 0.23%) of ergosterol peroxide was isolated from Naematoloma fasciculare Karst. Not only ergosterol peroxide but also ergosterol showed very strong anticomplementary activity on the classical pathway, the $IC_{50}$ values being $5.0 {\mu}M$ and $1.0 {\mu}M$, respectively. The $ ^{1}H $and $^{13}C$ NMR data of ergosterol peroxide were revised and completely assigned by DEPT, $^{1}H-^{1}H$ COSY, HMQC and HMBC correlations.

• Journal of the Korean Wood Science and Technology
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• 제35권6호
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• pp.145-151
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• 2007

산겨릅나무 수피의 성분 연구를 위해 수피를 채취하여 70% 아세톤 용액으로 추출하고 농축한 후 분획깔때기로 헥산, 디클로로메탄, 에틸아세테이트 및 수용성으로 순차 추출하여 동결건조하였다. 에틸아세테이트용성 분획에 대하여 Sephadex LH-20 칼럼크로마토그래피를 반복적으로 수행하여 5개의 페놀성 화합물을 분리하였다. 화합물의 구조는 $^1H-NMR$, $^{13}C-NMR$, 2D-NMR 및 MS 스펙트럼을 분석하여, (+)-catechin (1), (-)-epicatechin (2), (-)-epicatechin-3-O-gallate (3), gallic acid (4) 및 6''-O-galloylsalidroside (5)으로 동정하였다. (-)-epicatechin-3-O-gallate (3), gallic acid (4), 6''-O-galloylsalidroside (5)는 산겨릅나무 수피에서 처음 분리되었다.

• 분석과학
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• 제12권6호
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• pp.509-514
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• 1999

Titanium(IV) isoproxide에 유기첨가제로 아세트산을 첨가하여 단일성분계인 치환된 titanium(IV) isoproxide를 합성한다. 합성된 titanium 착화합물은 세가지 형태로 된 5배위 및 6배위의 구조로 존재함을 FT-IR, $^1H$ 및 $^{13}C$ NMR 그리고 UV-Vis 스펙트라로 확인하였다. 이 착물에 대한 가수분해 반응을 $^1H$-NMR spectroscopy를 이용해 관찰하였고 FT-IR spectroscopy로 가수분해 및 건조시킨 후의 구조 변화를 관찰하여 보았으며 리간드의 존재 유무도 살펴보았다.

• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1187-1191
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• 2010

$^1H-^{15}N$ heteronuclear dipolar coupling solid-state NMR experiments on lipid bilayer or bicelle samples are very useful for the structural studies of membrane proteins. However, to study these biological samples using solid-state NMR, a specific probe with high efficiency and high capability is required. In this paper, we describe the optimized design, construction, and efficiency of a 400 MHz wide-bore $^1H-^{15}N$ solid-state NMR probe with 5-mm solenoidal rf coil for high power, multi-pulse sequence experiments, such as 2D PISEMA or 2D SAMMY.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.93-99
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• 2011

Proton-NMR spectroscopic method was applied to kinetics study of concentrated sulfuric acid hydrolysis reaction. Xylan was used as model compounds. Without neutralization steps in proton-NMR methods, this analysis method is valid for analysis of xylose, furfural and formic acid in acid hydrolyzates.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.662-666
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• 2007

Poly(vinyl butyral) (PVB) with different wt% water was studied gravimetrically as well as with 1H magic angle spinning (MAS) nuclear magnetic resonance (NMR). The composition of PVB samples changes during MAS NMR because of the centrifugal force. As MAS time progresses, initially free water was removed fast but bound water also was gradually depleted. More water was diminished at faster spinning speeds, longer spinning time, higher temperatures, and higher initial water contents. As water in PVB was reduced, the chemical shifts and line widths of different types of water and also those of PVB changed. Our results demonstrate that 1H MAS NMR carried out at 10 kHz in less than about 5 minutes is a convenient and sensitive technique to measure: (a) the content variations of different types of water in polymers, (b) the degree of the interaction of water and polymer, and (c) the molecular dynamics of the polymer. Our study can be extended to different soft polymers with other small molecules than water in them.

• 대한화학회지
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• 제63권2호
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• pp.78-84
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• 2019

High-resolution $^1H$ NMR spectroscopic technique has been widely used as one of the most powerful analytical tools in food chemistry as well as to define molecular structure. The $^1H$ NMR spectra-based metabolomics has focused on classification and chemometric analysis of complex mixtures. The principal component analysis (PCA), an unsupervised clustering method and used to reduce the dimensionality of multivariate data, facilitates direct peak quantitation and pattern recognition. Using a combination of these techniques, the various green teas and black teas brewed were investigated via metabolite profiling. These teas were characterized based on the leaf size and country of cultivation, respectively.

• 한국축산식품학회지
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• 제41권2호
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• pp.312-323
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• 2021

The purpose of this study was to use 1H nuclear magnetic resonance (1H NMR) to quantify taste-active and bioactive compounds in chicken breasts and thighs from Korean native chicken (KNC) [newly developed KNCs (KNC-A, -C, and -D) and commercial KNC-H] and white-semi broiler (WSB) used in Samgye. Further, each breed was differentiated using multivariate analyses, including a machine learning algorithm designed to use metabolic information from each type of chicken obtained using 1H-13C heteronuclear single quantum coherence (2D NMR). Breast meat from KNC-D chickens were superior to those of conventional KNC-H and WSB chickens in terms of both taste-active and bioactive compounds. In the multivariate analysis, meat portions (breast and thigh) and chicken breeds (KNCs and WSB) could be clearly distinguished based on the outcomes of the principal component analysis and partial least square-discriminant analysis (R2=0.945; Q2=0.901). Based on this, we determined the receiver operating characteristic (ROC) curve for each of these components. AUC analysis identified 10 features which could be consistently applied to distinguish between all KNCs and WSB chickens in both breast (0.988) and thigh (1.000) meat without error. Here, both 1H NMR and 2D NMR could successfully quantify various target metabolites which could be used to distinguish between different chicken breeds based on their metabolic profile.