• Korean Journal of Pharmacognosy
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• 제23권1호
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• pp.20-23
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• 1992

A new method for the analysis of coumarin constituents in the roots of Peucedanum japonicum by high performance liquid chromatography was established. Among two coumarin constituents identified, peucedanol was confirmed to be applicable to a standard compound. A reversed phase system with a ${\mu}Bondapak$ C_{18}$, column using $H_2O-MeOH=5\;:\;4$ as a moble phase was developed. Peucedanol and a minor constituent, umbelliferone were detected at 333nm and the analysis was successfully carried out within 20 min.

• Korean Journal of Pharmacognosy
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• 제21권3호
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• pp.239-241
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• 1990

A new method for quantitative determination of byakangelicin in Angelicae dahuricae Radix by high performance liquid chromatography was established. A reversed-phase system with a ${\mu}Bondapak$ $C_{18}$ column using THF : dioxane : MeOH : HAc : 5% $H_3PO_4$ : $H_2O$=72.5 : 62.5 : 25 : 10 : 1 : 329 as a mobile phase was developed. Byakangelicin together with ter-O-byakangelicin and oxypeucedanin methanolate, and isooxypeucedanin as an internal reference were detected at 350 nm and the analysis was successfully carried out within 30 min.

• Korean Journal of Pharmacognosy
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• 제30권3호
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• pp.328-331
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• 1999

A new method for quantitative determination of p-methoxycinnamic acid in Scrophulariae radix by high performance liquid chromatography was established. A reversed-phase system with SPHERI-5 RP-18 5 micron $(250\;{\times}\;4.6\;mm)$ column using TFA (0.05%) and acetonitrile as a mobile phase was developed. p-Methoxycinnamic acid and N-(p-methoxycinnamoyl)-p-aminophenol as an internal reference were detected at 310 nm and the analysis was successfully carried out within 50 min.

• Korean Journal of Pharmacognosy
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• 제20권1호
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• pp.21-24
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• 1989

A new method for quantitative determination of icariin in Epimedii Herba by high performance liquid chromatography was established. A reversed-phase system with $a\;{\mu}Bondapak\;C_{18}$ column using methanol in water(15% to 70%, gradient elution) as a mobile phase was developed. Icariin and spinosin as an internal reference were detected at 350 nm and the analysis was successfully carried out within 30 min.

• Journal of the Korean Society for Heat Treatment
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• 제27권4호
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• pp.185-190
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• 2014

The influences of small amount of Sn addition on microstructure and creep resistance of AZ91-0.4%Ca alloy have been investigated. The microstructure of the AZ91-0.4%Ca alloy was characterized by ${\alpha}$-(Mg) dendrite cells surrounded by eutectic ${\beta}(Mg_{17}Al_{12})$ and $Al_2Ca$ phases. The 0.5%Sn addition resulted in the formation of rod-shaped CaMgSn particles with the extinction of $Al_2Ca$. The Sn-containing alloy exhibited better creep resistance below $175^{\circ}C$, but the tendency was reversed above $200^{\circ}C$. The reason was discussed in relation to the change in thermal stability of ${\beta}$ phase in response to the Sn addition.

• YAKHAK HOEJI
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• 제25권3호
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• pp.101-108
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• 1981

Quantitative determination of capsaicin in biological fluid was investigated. The pharmacokinetic study of capsaicin in rabbits was performed by high-pressure liquid chromatography, equipped with a microparticulate reversed-phase column and a fixed wavelength detector. Elution was carried out using methanolwater(70:30). It allows the quantitative determination at 8-400 ng level. When single dose of capsaicin(4mg/kg) was given to rabbits intravenously, the elimination phase was extremely short with average half-life to 17.35 minute. Urine excretion of capsaicin itself during first 2 hours after intravenous administration (4mg/kg) was 0.004-0.04% of the administered amount. The maximum plasma concentration of capsaicin after oral administration (300mg/kg) was $4{\times}10^{-7}$g/ml at 40 minutes. The $LD_{50}$ of capsaicin in mouse was 0.40mg/kg (i.v.) and 47.2 mg/kg (p.o.) which was determined by Litchfield and Wilcoxon's method, suggesting that the gastrointestinal absorption of capsaicin is poor.

• YAKHAK HOEJI
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• 제33권3호
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• pp.156-160
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• 1989

A gas-chromatographic determination method of thiamin which use a quantitative cleavage of thiamin to 4-methyl-5-(2-hydroxyethyl)thiazol [I] and solvent extraction of the analyte prior to GC injection was modified. A column chromatographic procedure using a reversed phase, high capacity solid phase cartridge was applied to the clean-up of the analyte. Thiazol derivative[I] was quantitatively recovered upon the column method. Acetanilide, an internal standard, has a good recovery through the analytical procedure. The method has analytical precision of 2% or less in the coefficient of variation.

• YAKHAK HOEJI
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• 제32권1호
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• pp.50-54
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• 1988

A simple and sensitive method was studied for the simultaneous determination of catecholamine, indoleamine and their related metabolites by high performance liquid chromatography with electrochemical detector. Norepinephrine, dopamine, serotonin and their metabolites of 3,4-dihydroxyphenylacetic acid, homovanillic acid, 5-indoleacetic acid were resolved from rat brain tissue homogenates by separation on reversed phase $C_{18}$ column with mobile phase consisting of monochloroacetate buffer (pH2.47), 1.42mM sodium octyl sulfonate and 7% acetonitrile. Both catechols and indoles can be eluted in 15min. The sensitivities of this method are sufficient for determination of at least 100 pg of neurochemical amines in brain samples, for example, frontal cortex, olfactory bulb, striatum, septum, hippocampus, thalamus, hypothalamus, medulla & pons and cerebellum. The highest level of dopamine was observed in striatum whereas norepinephrine and serotonin were in hypothalamus.

• YAKHAK HOEJI
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• 제31권5호
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• pp.315-321
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• 1987

A high performance liquid chromatographic method was developed for the determination of glycyrrhetinic acid contained in licorice powder. Glycyrrhetinic acid which is hydrolysate of glycyrrhizin extracted from licorice powder, was determined with good result by HPLC using 2-bromoacetyltriphenylene labeling reagent. The glycyrrhetinic acids were labeled with 2-bromoacetyltriphenylene in acetonitrile using 18-crown-6-ether and KOH as a catalyst. Derivatized glycyrrhetinic acids were separated from the extracted licorice powder on a reversed-phase column (chemopak $C_{18}$) using 100% acetonitrile as a mobile phase and monitored by an UV-detector at 268nm. Linearity of calibration curve was obtained between 5 ng and 20 ng, and the lower limit of detection was 2 ng. The recovery of glycyrrhetinic acid to licorice powder was about 99.3%. This method was sensitive, reliable and useful for, determination of glycyrrhetinic acid.

• Archives of Pharmacal Research
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• 제22권6호
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• pp.608-613
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• 1999

Optimum conditions of chiral derivatization reaction of $\beta$-blockers (acebutolol, arotinolol, betaxolol, bisoprolol, celiprolol, metoprolol and pindolol) with (-)-menthyl chloroformate were investigated for the resolution by HPLC. With more than 30 times molar excess of (-)-methyl chloroformate chiral derivatization reactions were completed within one hour at room temperature except arotinolol and celiprolol. Diastereomeric derivatives of $\beta$-blockers were well resolved on the ODS column using acetonitrile-methanol-water as a mobile phase.