• Analytical Science and Technology
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• v.34 no.2
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• pp.78-86
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• 2021

The objective of this study was to investigate urinary cut-off concentrations of quetiapine and risperidone for distinction between normal and abnormal/non-takers who were being placed on probation. Liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was employed for determination of antipsychotic drugs in urine from mentally disordered probationers. The optimal cut-off values of antipsychotic drugs were calculated using receiver operating characteristic (ROC) curve analysis. The sensitivity and specificity of the method for the detection of antipsychotic drugs in urine were subsequently evaluated. The area under the ROC curve (AUC) was 0.927 for norquetiapine and 0.791 for 9-hydroxyrisperidone, respectively. These antipsychotic drugs are classified readily in the ROC curve analysis. The cut-off values for distinguishing regular and irregular/non-takers were 39.1 ng/mL for norquetiapine and 67.9 ng/mL for 9-hydroxyrisperidone, respectively. The results of this study suggest the cut-off values of quetiapine and risperidone were highly useful to distinguish regular takers from irregular/non-takers.

• Analytical Science and Technology
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• v.14 no.1
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• pp.44-49
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• 2001

Solid-phase microextraction (SPME) with $85{\mu}m$ polyacrylate fiber, coupled to gas chromatography-mass spectrometry was used to analyze the plasticizers contained in balloon samples. The balloons were identified to be made of polyisoprene by IR spectroscopy. The plasticizers extracted from the balloon samples soaked in acetone-added water solvent for an hour were quantified by external standard method using nine kinds of plasticizers. The quantification method was validated for standard plasticizers in the range of $0.25-25{\mu}g/g$. The detection limits were $0.11-0.38{\mu}g/g$ for different plasticizers. The RSDs for the reproducibility of this quantitation method were 3.7-14.2%. A few of balloons included risky level of plasticizer concerned as and endocrine disrupter, and it is necessary to regulate these products.

• Analytical Science and Technology
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• v.20 no.3
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• pp.198-203
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• 2007

The analysis method of 3-Monochloropropane-1,2-diol (3-MCPD) compound in water was developed using liquid chromatography with mass spectrometric detection. Aqueous solution was controlled in strong basic condition with sodium hydroxide, and then $25{\mu}L$ of benzoyl chloride was added to the solution for the derivatization of 3-MCPD. The derivative was extracted using pentane and analyzed by the selected ion monitoring (SIM) method of LC-MS. The results of analyses showed that the calibration curves was in the range of 1.0 to $100{\mu}g/mL$ with a good linearity (correlation coefficient of $r^2=0.992$) and limit of detection was below $0.01{\mu}g/mL$. The recoveries of this analysis method by LC-MS were 92.3-98.0 %.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2102-2104
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• 2004

In this study, sheathless electrospray from PDMS/glass microchips with conducting metal emitter tip is described. A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system has advantages of the CE separation and on-line electrospray detection of peptide solution. We have fabricated a new electrospray ionization(ESI) device composed of the metal emitter tip and CE separation channel monolithically in a glass microchip. The separation channel and metal emitter tip are fabricated using a glass wet etching and gold electro plating process, respectively. The fabricated micro electrospray chip was tested by spraying peptide sample for mass spectrometric analysis. Singlely-charged peak and doublely-charged peak of peptide were detected and further MS/MS fragmentation was performed in each peak. Direct comparisons with conventional glass or fused silica emitters showed very similar performance with respect to signal strength and stability.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2741-2747
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• 2012

A new series of 2,5-disubstituted-1,3,4-thiadiazoles 6a-i was synthesized by overnight stirring various 1,4-disubstituted thiosemicarbazides 5a-i in polyphosphoric acid followed by neutralization. The structures of newly synthesized compounds 5a-i and 6a-i were characterized by IR, $^1H$ and $^{13}C$ NMR, elemental analysis and mass spectrometric studies. All the synthesized compounds were evaluated for their urease and acetylcholine esterase inhibition activities. Thiosemicarbazides 5a-i are found to possess excellent potential for urease inhibition, more than the standard drug. Thiosemicarbazides 5a-i are more potent urease inhibitor than their cyclic analogues thiadiazoles 6a-i. Almost all of the compounds are excellent inhibitors of acetylcholine esterase. The inhibition of acetylcholine esterase of compounds 5a, 5c, 5d, 5g, 5i, 6e, 6f, 6g, and 6i is much more than that of standard drug.

• KSBB Journal
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• v.29 no.5
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• pp.380-384
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• 2014

Inhibition effects of peptide hydrolysates from Astragalus membranaceus Bunge. on the expression of the matrix metalloproteinases (MMPs) in human dermal fibroblasts were evaluated in vitro. Crude peptides were obtained by the hydrolysis of proteins extracted from A. membranaceus. Peptides were purified partially by the basis on the molecular weight using 40% polyacrylamide gel electrophoresis before treatment with human dermal fibroblasts. Basis on the doseeffect experiments, expressions of MMPs including MMP-1, MMP-3, MMP-8, MMP-13 in human dermal fibroblasts were evaluated. Expressions of MMP-1, MMP-3, MMP-8 and MMP-13 were reduced in 43%, 5%, 22% and 57% respectively. The mass spectrometric analysis of partially purified peptides from A. membranaceus, which strongly inhibit expressions of MMPs, indicated that the peptides were composed of molecules below 1500 Da.

• Natural Product Sciences
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• v.24 no.3
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• pp.213-218
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• 2018

Chemical investigation of the plant Tristemma hirtum P. Beauv (Melastomataceae) resulted to the isolation of a new flavonol glycoside named quercetin-7-O-${\alpha}$-D-arabinofuranoside (1), together with nine known compounds including 3'-hexadecanoyl-2'-(9aZ)-tetradecanoyl-glycerol 1'-O-[${\beta}$-D-galactopyranosyl-(1'' ${\rightarrow}$ 6'')-${\alpha}$-D-galactopyranoside] (2), arjunolic acid (3), ${\beta}$-sitosterol-3-O-${\beta}$-D-glucopyranoside (4), terminolic acid (5), quercetin (6), asiatic acid (7), maslinic acid (8), $1{\beta}$-O-galloylpedunculagin (9) and 6-hydroxyapigenin 7-O-${\beta}$-D-glucopyranoside (10) from the methanol extract using normal and reversed phase column chromatography. The structures of these compounds were determined by comprehensive interpretation of their spectral data mainly including 1D- 2D-NMR ($^1H-^1H$ COSY, HSQC, and HMBC) spectroscopic and ESI-TOF-MS mass spectrometric analysis.

• YAKHAK HOEJI
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• v.31 no.1
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• pp.33-39
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• 1987

In order to elucidate the defence mechanism of Cyprinus carpio nudus to Clonorchis sinensis, clonorchicidal substance in the epidermal mucus of this fish was isolated by silica gel column and thin layer chromatography and analyzed for its chemical nature by UV, IR and NMR-spectroscopy. The epidermal mucus of the fish was extracted by ethyl ether and separated into 2 fractions by column chromatography using petroleum ether/chloroform(30/70,v/v) as first solvent and methanol as second solvent. The second fraction with greyish white colour showed clonorchicidal effect. The second was again fractionated into greyish white precipitate and clonorchicidal greenish yellow supernatant fraction, by adding petroleum ether and standing the mixture for 5 days at $5^{\circ}C$. The latter was divided into 7 fractions in column chromatography with acetone/ benzene (10/90, v/v) as carrier. The fraction on equivalent to the spot of Rf. 0.225 value among them disclosed the strongest clonorchicidal effect. By this purification procedure, clonorchicidal substance was purified 154-fold with 0.9% yield from the mucus of the fish, and 10mg of the final fraction killed tne metaceicariae in 22 min. Infra red, nuclear magnetic resonance and ultraviolet spectrometric analysis of the purified substance revealed that the substance is linoleic acid. According to the results of the present studies it seemed that this fish could not be proper intermediate host of Clonorchis sixensis, and that defence mechanism of this fish to the worm seems to be correlated with clonorchicidal substance in epidermal mucus.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.2
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• pp.71-75
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• 2010

To investigate the intestinal absorption of a fibrinolytic and proteolytic lumbrokinase extracted from Eisenia andrei, we used rat everted gut sacs and an in situ closed-loop recirculation method. We extracted lumbrokinase from Eisenia andrei, and then raised polyclonal antibody against lumbrokinase. Fibrinolytic activity and proteolytic activity in the serosal side of rat everted gut sacs incubated with lumbrokinase showed dose- and time-dependent patterns. Immunological results obtained by western blotting serosal side solution using rat everted gut sacs method showed that lumbrokinase proteins between 33.6 and 54.7 kDa are absorbed mostly by the intestinal epithelium. Furthermore, MALDI- TOF mass spectrometric analysis of plasma fractions obtained by in situ recirculation method confirmed that lumbrokinase F1 is absorbed into blood. These results support the notion that lumbrokinase can be absorbed from mucosal lumen into blood by oral administration.

• Textile Coloration and Finishing
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• v.13 no.5
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• pp.24-24
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• 2001

Kinetics and mechanism for alkaline hydrolysis of C. I. Disperse Blue 79(B-79) which is 4-N, N-diacetoxyethyl-2-acylamino-5-ethoxy -2′-bromo-4′,6′-dinitroazobenzene were investigated. The color strength of B-79 in acetone/water solutions of various NaOH concentrations decreased continuously. The hydrolysis rate of B-79 increased with increasing alkali concentration and appeared following first order reaction. The observed rate constants for various concentrations of B-79 showed similar values, and B-79 was hydrolyzed by first order reaction for dye concentration. Therefore, it was confirmed that the overall reaction follow second order kinetics and proceed via S/sub n/2 reaction. From the study on kinetics and spectrometric analysis, it was proposed that the rate determining step of the hydrolysis reaction of B-79 is the nucleophilic substitution reaction - that is the reaction of the rapid attack of $OH^{-}$ on the carbon atom, which is in acceptor ring, adjacent to azo group to break the C-N bond. And it was also found that the final hydrolysis products of B-79 include both the acceptor ring in the form of sodium salt and the donor ring possessing 4-N,N-dihydroxyethyl group converted from 4-N,N-diacetoxyethyl group.