• Title/Summary/Keyword: Nonpolar solvent

Search Result 72, Processing Time 0.028 seconds

THE COMBINATION OF CHEMOMETRICS AND 2D NIR CORRELATION SPECTROSCOPY IN THE ANALYSIS OF DENATURATION PROCESS

  • Czarnik-Matusewicz, Boguslawa;Murayama, Koichi;Wu, Yuqing;Ozaki, Yukihiro
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
    • /
    • 2001.06a
    • /
    • pp.1286-1286
    • /
    • 2001
  • Despite extensive theoretical and experimental studies the structure of the protein-solvent interface is subject of many controversy. Understanding the processes that occur in aqueous solution requires understanding of the solvent influence on the structure of protein. The aim of this study is to investigate the applicability of NIR methods in the study of hydration phenomena in protein solutions. Temperature-induced changes in NIR spectra of -lactoglobulin (BLG) in aqueous solutions have been investigated by means of two-dimensional correlation spectroscopy (2DCOS) and principal component analysis (PCA). With the temperature increase the balance of forces between the BLG's interaction with itself and the BLGs interaction with its environment is disrupted leading to BLG unfolding. Significant differences of 2D signals and distinct discrepancies of loading on PC1 and PC2 were observed as a result of temperature increase. In the native folded conformation of BLC, most of the nonpolar amino acids are hidden in the centre of the structure, out of contact with water molecules, while charged groups are outside, in the contact with water. The polar groups promote low density Ih-type structure in the water outside this first hydration shell. When BLG unfolds it assumes a more extended configuration on which the previously buried nonpolar groups are exposed to water and promote the higher density II-type structure outside its first shell. Detailed assignments of bands attributed to the bulk water, different states of the hydrated water and the changed conformation of BLG are proposed.

  • PDF

Extraction of PCBs by Subcritical Water Extraction (Subcritical Water Extraction에 의한 PCBs 추출)

  • Kwak, Dong Hwan;Moon, Ji Yong;Lee, Sung In;Jeong, Gi Ho
    • Analytical Science and Technology
    • /
    • v.13 no.4
    • /
    • pp.511-519
    • /
    • 2000
  • Water in the supercritical state ($T{\geq}374^{\circ}C$, $p{\geq}221$ atm) is a good solvent for nonorganic pollutants, but it is extremely corrosive. Subcritical Water Extraction (SWE) is a very fast and an efficient method to extract nonpolar environmental pollutants adsorbed on the sediments and soils. Many nonpolar organic compounds are sufficiently soluble to be extracted to the water under subcritical conditions. Complete extraction of PCBs from the sediments and soils takes only a few minutes by applying SWE with the subcritical water at 50 atm and at $260^{\circ}C$.

  • PDF

Recovery of Cholesterol from the $\beta$-Cyclodexgtrin-Cholestrerol Complex Using Immobilized Cyclomaltodextrinas of Alkalophilic Bacillus sp. KJ 133

  • Kwon, Ho-Jeong;Jung, Hye-Jin;Kwak, Hae-Soo
    • Journal of Microbiology and Biotechnology
    • /
    • v.11 no.4
    • /
    • pp.712-715
    • /
    • 2001
  • A new combined method including the enzymatic hydrolysis of $\beta$-cyclodextrin ($\beta$-CD) and solvent extraction fo cholesterol from the hydrolyzed mixture was developed to recover cholesterol from a $\beta$-CD-cholesterol complex prepared from dairy products, such as cream, milk, and cheese. Cyclomaltodextrinase (cyclomatodextrin dextrin hydrolase, EC 3.2.1.54, DCase_ prepared form alkalophilic Bacillus sp. KJ 133 hydrolyzed the $\beta$-DC of the $\beta$-CD-cholesterol complex, and then, free cholesterol was efficiently extracted from the hydrolyzed mixture by a nonpolar solvent such as ethyl acetate. To increase the stability of free CDase, immobilized CDase was developed using sodium alginate as a carrier. The immobilized CDase showed a high recovery yield of cholesterol in a time-dependent manner compared to the free CDase. A gas chromatography analysis showed that more than 70% of cholesterol was recovered from the $\beta$-DC-cholesterol complex of cream by the immobilized CDase, whereas only 3% and 29% of cholesterol were recovered when the solvent extraction and free CDase treatment were used, respectively. The cholesterol recovered can be used as a raw material for steroid synthesis. Furthermore, this method can be an efficient way to recover cholesterol or other organic compounds that are bound in a $\beta$ -DC-cholesterol or -organic compound complex.

  • PDF

Solvent and Concentration Effects on Carbonyl Stretching Frequencies: Dialkyl Ketones (카르보닐 신축진동 파수에 대한 용매 및 농도 효과: 디알킬 케톤)

  • Jung, Young-Mee;Kang, Jae-Soo;Nam, Sang-Il;Lee, Mu-Sang
    • Journal of the Korean Chemical Society
    • /
    • v.40 no.6
    • /
    • pp.415-419
    • /
    • 1996
  • Hydrogen bonding, dielectric effects and steric effects are all factors which determine the carbonyl stretching frequency, νC=O of ketones in solution. The νC=O frequency of ketones is affected by change in concentration of ketones in various solvents. The νC=O frequency shifts to lower frequency in nonpolar solvents and shifts to higher frequency in polar solvents with the increasing volume% of ketones. In acetonitrle, the νC=O frequency shifts to higher frequency as the volume% of ketones is increased except dimethyl ketone. The νC=O frequency shifts to lower frequency as the solvent system becomes increasingly polar or with the increasing extent of intermolecular hydrogen bonding, as in the case of increasing volume% chloroform in $CHCl_3$/$CCl_4$ solvent system.

  • PDF

Extraction Characteristics of Dried Asian Lacquer by Solvents Before and After UV Degradation (자외선 열화 전후 건조 옻의 용매별 용출 특성)

  • Park, Jongseo;Schilling, Michael R.;Khanjian, Herant;Heginbotham, Arlen
    • Journal of Conservation Science
    • /
    • v.36 no.2
    • /
    • pp.103-111
    • /
    • 2020
  • To compare the cleaning effect of solvents such as water and ethanol used to clean lacquer relics, the components extracted with various solvents were analyzed. A freshly dried lacquer sample and a lacquer sample exposed to ultraviolet radiation for 24 days were treated with water, ethanol, acetone, and hexane, and the dissolved material was detected by pyrolysis-gas chromatography-mass spectrometry. The amount extracted was significantly higher in acetone and ethanol than in hexane, a nonpolar solvent. Water, a highly polar solvent, was relatively efficient for extracting low-molecular-weight materials. After experiencing 24 days of ultraviolet radiation, the lacquer exhibited a significant increase of extracted materials compared with the nonexposed one. This may be due to the degradation of the urushiol chain in the form of polymers, resulting in the formation of low-molecular-weight polar substances, including dicarboxylic acids. In addition to the deterioration status of lacquer relics, such solvent extraction properties will be a crucial consideration in selecting the appropriate cleaning solvent.

Screening for Potato Lipoxygenase-II Inhibitor in Unused Marine Resources by the Polarographic Method- (수산 미이용자원 중에 존재하는 효소적 산화 억제제의 검색 -2. 감자 Lipoxygenase-II에 의한 효소적 산화에 대한 억제-)

  • Cho, Soon-Yeong;You, Byeong-Jin;Chang, Mi-Hwa;Lee, Soo-Jung;Sung, Nak-Ju;Lee, Eung-Ho
    • Applied Biological Chemistry
    • /
    • v.37 no.6
    • /
    • pp.451-455
    • /
    • 1994
  • To detect naturally occurring bioactive compounds from unused marine resources, the screening for the 5-lipoxygenase(potato lipoxygenase-II) inhibitors in Asterina pectinifera, Halocynthia roretzi skin, Nototodarus sloani ink, Anthocidaris crassispina skin, Sargassum horneri, Agarum cribrosum, Odonthalia corymbifera and Desmarestia ligulata was carried out. Water, ether, acetone and methanol fractions extracted from Sargassum horneri had strong inhibitory effect on enzymatic lipid oxidation by potato lipoxygenase-II, and their $IC_{50}$ were 320, 18, 9.5 and $100\;{\mu}g/mL$, respectively. The $IC_{50}$ of ether fraction extracted from Asterina pectinifera and acetone fraction extracted from Nototodarus sloani ink were 29.5 and $34.3\;{\mu}g/mL$, and these extracts showed relatively excellent inhibitory activity. Nonpolar solvent (ether, acetone) extracts of tested marine organisms had more inhibitory effect against 5-lipoxygenase than the polar solvent(water) extracts.

  • PDF

Utilization of Liquid Chromatography Mass Spectroscopy for Screening Analysis of Acetogenins in Extracts of Asimina triloba Leaves (포포나무 잎 추출물에 존재하는 Acetogenin 확인을 위한 액체크로마토그래피 질량분석기의 활용)

  • Im, Do-Youn;Lee, Kyoung-In
    • Korean Journal of Pharmacognosy
    • /
    • v.49 no.3
    • /
    • pp.278-284
    • /
    • 2018
  • Asimina triloba contains many kinds of annonaceous acetogenins known to have toxicity and/or activity. In this study, analysis of acetogenins was carried out on the extract and its solvent fractions of A. triloba leaves using a liquid chromatography mass spectroscopy(LC-MS). In the extract, the ethanolic extract was significantly higher acetogenin contents than hot water extract. In the analysis of solvent fraction from the ethanolic extract, n-hexane, ethylacetate, and aqueous fraction were contained 85.17~90.92%, 8.96~14.52% and 0.12~0.35% of total acetogenin in the extract. Based on these results, the analytical method is useful for comparing annonaceous acetogenins contents in plant samples. Moreover, when research or product development aiming at the physiological activity of acetogenin such as anticancer activity using A. triloba leaves is performed, a fractionation using a nonpolar organic solvents and alcohol extract may be useful methods. This method can also be used for the purpose of eliminating toxicity as well.

Self-Aggregation of Synthetic Magnesium Bacteriochlorins as a Photosynthetic Antenna Model

  • Kunieda, Michio;Mizoguchi, Tadashi;Tamiaki, Hitoshi
    • Journal of Photoscience
    • /
    • v.9 no.2
    • /
    • pp.353-355
    • /
    • 2002
  • We prepared 3-(1-hydroxyethyl)-bacteriopyrochlorophy11-a (3) possessing magnesium atom and phytyl ester from modification of natural bacteriochlorophyll(BChl)-a. A dichloromethane solution of (3$^1$R) and (3$^1$S)-3 was diluted with 100~1000 fold volume of cyclohexane to give new species absorbing near-infrared lights. The resulting Q, maximum of (3$^1$R)-3 was 860 nm and red-shifted by 2150 $cm^{-1}$ / from the monomeric. In the nonpolar organic solvent, epimeric (3$^1$S)-3 showed a 1ess red-shifted peak at 798 nm as well as a residual monomeric band. Such visible spectra indicated that 3 diastereose1ectively aggregated in cyclohexane to afford oligomers possessing a simi1ar supramolecular structure with chlorosomal aggregates of natural BChl-d, 7,8-dehydro-form of 3.

  • PDF

Identification of Antimutagenic Compound from Kale by High Performance liquid Chromatography and Mass Spectrometry

  • Lee, Seon-Mi;Rhee, Sook -Hee;Yoo, Jong-Shin;Park, Kun-Young
    • Preventive Nutrition and Food Science
    • /
    • v.3 no.4
    • /
    • pp.334-338
    • /
    • 1998
  • Kale(Brassica oleracea var. acephala) is one of Cruciferous vegetables that is closely related to the wild ancestral form of cabbabe. The ethanol extract of kale which contains the active compoundsss under Salmonella assay system was fractionated with chloroform to collect the nonpolar solvent soluble compounds, and then further fractionation was carried out by silica gel column chromatography. Among kale extracts separated by silical gel column chromatography, the fractions of 4, 5 and 6 exhibited strong antimutagenic activities. The major active compounds from the fraction were identified as chlorophyll derivatives by the analysis with HPLC-fritp-MS. The molecular weights of each chlorophyll derivatives in the sample were acquired from the peaks of positive ion atomosphere pressure chemical ionization (APCI) mas spectrometry.

  • PDF

Herb-Processing Methods for Ginkgo Folium (백과엽(白果葉)(은행잎)의 포제법에 대한 제언(提言))

  • Kim, Myung-Gyou;Leem, Kang-Hyun
    • The Korea Journal of Herbology
    • /
    • v.20 no.4
    • /
    • pp.11-16
    • /
    • 2005
  • Objectives : This study was designed to propose the effective herb-processing method of Ginkgo Folium in the Oriental medicine. Methods : The books, papers and patents were used to examine the recent usage of Ginkgo Folium. Results : The toxic ingredients of Ginkgo Folium should be removed. Accordingly, a detoxification process using a nonpolar solvent and a vinegar-roasting process in sequence are desirable to assure its safety. The previously developed standard extract (e.g. EGb 761) could be used as a powdered Oriental medicine as well. Conclusions : Ginkgo Folium could not be used widely to treat the diseases in ancient Oriental medicine, because the toxic ingredients could not be removed by any method until recent year. However, Ginkgo Folium might be used as a herbal medicine that invigorates the blood without any difficulty using herb-processing methods suggested in this paper.

  • PDF