• Analytical Science and Technology
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• v.10 no.5
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• pp.307-314
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• 1997

Inductively coupled plasma atomic emission spectrometry(ICP/AES) was used for the determination of uranium and thorium in geological materials. Samples were predecomposed by mixed acid digestion technique. The separation of the uranium and thorium was achieved by systematic solvent extraction with TTA(thenoyltrifluoroacetone) and TOA (tri-n-octylamine) and back extraction into HCl. The results for standard rock sample, NIST SRM 278, showed a good agreement with those certified from NIST as well as found values by other non-destructive techniques. Additional purification for extracted portions was carried out by anion exchange chromatography for measurement of several natural radioisotopes of uranium and thorium by alpha spectrometry.

• Food Science and Preservation
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• v.22 no.4
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• pp.553-558
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• 2015

The aims of this study was to optimize the extraction conditions of sinigrin from Dolsan leaf mustard. Dolsan leaf mustard (Dolsan-eup, Yeosu-si) harvested during at May 2014 was used for sinigrin extraction. After the extraction of sinigrin using 50% $CH_3CN$, 10% $NH_4Cl$, 60% $CH_2OH$, and 70% $CH_3OH$, the sinigrin content was measured by HPLC analysis. The results showed that sinigrin content was highest with 50% $CH_3CN$ solvent extraction and UV detector sensitivity was greater at 228 nm rather than at 242 nm. The sinigrin concentrations of leaf, stem and root with 50% $CH_3CN$ extraction were 345 ppm, 728 ppm, and 539 ppm, respectively. After extraction of the different parts of Dolsan leaf mustard, The standard retention time by HPLC analysis of sinigrin content was 2.054, 2.032, 2.059, and 2.035 min from the root, stalk, and leaf, respectively. On the other hand, HPLC analysis showed that the leaf extracts contained glucoraphanin, one of glucosinolates. The optimum time and extraction solvent for the sinigrin extraction from Dolsan leaf mustard was found to be 24 hr with 50% $CH_3CN$ solvent. In addition, opotimum UV detector k at 228 nm. These results showed that the optimum extraction conditions for Dolsan leaf mustard were 24 hr extraction with 50% $CH_3CN$ solvent. In addition, the optimum wavelength of UV detector was determined to be 228 nm for sinigrin analysis. Therefore, this study could provide a useful information for sinigrin extraction and its systematic analysis during the storage.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.362-377
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• 2014

Polycyclic aromatic hydrocarbons (PAHs) have been of particular concern since they are present both in the vapor and particulate phases in ambient air. In this study, a simple method was applied to determine the vapor phase PAHs, and the performance of the new method was evaluated with a conventional method. The simple method was based on adsorption sampling and thermal desorption with GC/MS analysis, which is generally applied to the determination of volatile organic compounds (VOCs) in the air. A combination of Carbotrap (300 mg) and Carbotrap-C (100 mg) sorbents was used as the adsorbent. Target compounds included two rings PAHs such as naphthalene, acenaphthylene, and acenaphthene. Among them, naphthalene was listed as one of the main HAPs together with a number of VOCs in petroleum refining industries in the USA. For comparison purposes, a method based on adsorption sampling and solvent extraction with GC/MS analysis was adopted, which is in principle same as the NIOSH 5515 method. The performance of the adsorption sampling and thermal desorption method was evaluated with respect to repeatabilities, detection limits, linearities, and storage stabilities for target compounds. The analytical repeatabilities of standard samples are all within 20%. Lower detection limits was estimated to be less than 0.1 ppbv. In the results from comparison studies between two methods for real air samples. Although the correlation coefficients were more than 0.9, a systematic difference between the two groups was revealed by the paired t-test (${\alpha}$=0.05). Concentrations of two-rings PAHs determined by adsorption and thermal desorption method consistently higher than those by solvent extraction method. The difference was caused by not only the poor sampling efficiencies of XAD-2 for target PAHs and but also sample losses during the solvent extraction and concentration procedure. This implies that the levels of lower molecular PAHs tend to be underestimated when determined by a conventional PAH method utilizing XAD-2 (and/or PUF) sampling and solvent extraction method. The adsorption sampling and thermal desorption with GC analysis is very simple, rapid, and reliable for lower-molecular weight PAHs. In addition, the method can be used for the measurement of VOCs in the air simultaneously. Therefore, we recommend that the determination of naphthalene, the most volatile PAH, will be better when it is measured by a VOC method instead of a conventional PAH method from a viewpoint of accuracy.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.143-147
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• 2008

To develop a new anti-wrinkle agent from medicinal plants, this study investigated the optimal conditions for extracting elastase inhibitor from Rheum undulatum L. Maximal extraction occurred by using 70% methanol at $50^{\circ}C$ for 24 hr; the elastase inhibitory activity was 60.4%($IC_{50}:6.7{\times}10^3{\mu}g/m{\ell}$). Systematic solvent extraction, thin layer chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, and reverse-phase high performance liquid chromatography were used in the partial purification of the elastase inhibitor. The compound was soluble in dimethylsulfoxide, methanol, and ethanol, and had maximum absorption spectra at 231.5 nm and 275.5 nm.

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.57-61
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• 2010

For development of anti-obesity nutraceuticals from mushrooms, new anti-obesity lipase inhibitor from Phellinus linteus was purified by systematic solvent extraction, TLC and HPLC and characterized. Methanol extract from P. linteus most effectively inhibited(72.5%) porcine pancreatic lipase and ethyl acetate fraction showed the highest inhibitory activity in the systematic solvent extraction. A lipase inhibitor from the ethyl acetate fraction was purified through following steps including 3 times silica gel chromatography and preparative HPLC. The purified lipase inhibitor was a yellowish geen powder and its $IC_{50}$ value was 175 ng. Its molecular weight by MALDI-TOF-MS was 523.06 Da and showed maximal absorption spectrum at 225.1 nm.

• Mycobiology
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• v.38 no.1
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• pp.52-57
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• 2010

To develop a potent anti-obesity lipase inhibitor from mushroom, the lipase inhibitory activities of various mushroom extracts were determined. Methanol extracts from Phellinus linteus fruiting body exhibited the highest lipase inhibitory activity (72.8%). The inhibitor was maximally extracted by treatment of a P. linteus fruiting body with 80% methanol at $40^{\circ}C$ for 24 hr. After partial purification by systematic solvent extraction, the inhibitor was stable in the range of $40\sim80^{\circ}C$ and pH 2.0~9.0. In addition to lipase inhibitory activity, the inhibitor showed 59.4% of superoxide dismutase-like activity and 56.3% of acetylcholinesterase inhibitory activity.

• The Korean Journal of Food And Nutrition
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• v.24 no.3
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• pp.291-294
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• 2011

A lipase inhibitor from Desmodium oxyphyllum DC. was purified by methanol extraction, systematic solvent extraction, silica gel column chromatography, $C_{18}$ solid phase extraction chromatography and RP-HPLC. We obtained the purified lipase inhibitor with 182 ng($IC_{50}$) of lipase inhibitory activity for a 0.06% yield. Its molecular weight was estimated to be 655.37 Da from an instrumental analysis of MALDI-TOF-MS and it was identified copper-3,5-dibromo-2-hydroxybenzoic acid ($C_{14}H_8Br_4CuO_6$) by $^1H$, $^{13}C$ NMR analysis.

• Korean Journal of Medicinal Crop Science
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• v.17 no.6
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• pp.434-438
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• 2009

For the development of a new antidementia functional food or alternative drug using agricultural products, Job's tears (Coix lachrymajobi L.), which shows high acetylcholinesterase (AChE) inhibitory activity (55.1%) was selected and the extraction conditions of AChE inhibitor were optimized. AChE inhibitor of Job's tears was maximally extracted when it was treated with 60% methanol at $40^{\circ}C$ for 6 h. The AChE inhibitor of the methanol extracts was partially purified by systematic solvent extraction, thin layer chromatography, silica gel chromatography and reverse-phase HPLC and the partial purified AChE inhibitor with inhibitory activity ($IC_{50}$) of $0.608\;{\mu}g$ was obtained. The partial purified AChE inhibitor was soluble in methanol and hexane, and insoluble in water. Its maximum absorption spectra was 230 nm and also it was stable in the range of $30^{\circ}C$ and $70^{\circ}C$ and pH 4.0-8.0 for 1 h.

• Mycobiology
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• v.36 no.2
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• pp.102-105
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• 2008

The acetylcholinesterase (AChE) inhibitor of Yarrowia lipolytica S-3 was maximally produced when it was incubated at $30^{\circ}C$ for 36 h in an optimal medium containing 1% yeast extract, 2% peptone and 2% glucose, with an initial pH 6.0. The final AChE inhibitory activity under these conditions was an $IC_{50}$ value of 64mg/ml. After partial purification of the AChE inhibitor by means of systematic solvent extraction, the final $IC_{50}$ value of the partially purified AChE inhibitor was 0.75 mg/ml. We prepared a test product by using the partially purified AChE inhibitor and then determined its stability for the development of a new antidementia commercial product. The test product was stable at room temperature for 15 weeks.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.489-494
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• 2008

In order to develop a potent antidementia $\beta$-secretase inhibitor from phytochemicals, $\beta$-secretase inhibitory activities of extracts from many medicinal plants and herbs were determined. Water extracts from Rubus coreanus showed the highest $\beta$-secretase inhibitory activity of 84.5%. After purification of the $\beta$-secretase inhibitor from R. coreanus using systematic solvent extraction, ultrafiltration, Sephadex G-10 column chromatography, and reverse-phase high performance liquid chromatography (HPLC), a purified $\beta$-secretase inhibitor with $IC_{50}$ inhibitory activity of $6.3{\times}10^3\;ng/mL$ ($1.56{\times}10^{-6}\;M)$ was obtained with a 0.08% solid yield. The molecular mass of the purified $\beta$-secretase inhibitor was estimated to be 576 Da by liquid chromatography-mass spectrometry (LC-MS) and $\beta$-secretase inhibitor also is a new tetrapeptide with the sequence Gly-Trp-Trp-Glu. The purified $\beta$-secretase inhibitory peptide inhibited $\beta$-secretase non-competitively and also show less inhibition on trypsin, however no inhibition on other proteases such as $\alpha$-secretase, chymotrypsin, and elastase.