• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.559-563
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• 2012

An analytical method for the simultaneous determination of veterinary medicines (amprolium and decoquinate) in cattle and chicken's muscle by HPLC/UV-vis was established. Samples were extracted by a HLB (Hydrophilic-Liphophilic Balance) cartridge with acetonitrile and methanol. Prior to HPLC injection, a mixture solvent (Water:MeOH, 1:1) was utilized as a reconstitution solvent. Chromatographic separation was achieved with a C18 column ($250{\times}4.6mm$, $5{\mu}m$) using gradient elution with 20 mM HFBA and MeOH:ACN (1:1.8). The calibration curves from the spiked blank matrix showed good linearity (above $r^2$=0.997) in the concentration range of $0.13-12.0mg\;kg^{-1}$. The relative recovery (accuracy) and limit of quantitation (LOQ) were in the range of 78.5-107.1% and $0.13-0.42mg\;kg^{-1}$, respectively. The developed method can be used to determine under the MRL (Maximum Residue Limits) levels of veterinary medicines in animal tissues.

• Korean Journal of Agricultural Science
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• v.38 no.2
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• pp.295-299
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• 2011

The content of hesperidin in the mixed tea, which was composed of dried orange peel, laurel leaf, mulberry leaf, silver magnolia leaf, oriental melon tap, cassia seed, and licorice root, was determined by high performance liquid chromatography (HPLC). Hesperidin was quantified by a reverse phase column with gradient solvent system (watcr:acetonitrile = 80:20 to 35:65 for 30 min) and UV/VIS detection (280 nm). The How rate was kept constant at 1.0 ml/min. The content of hesperidin in the mixed tea was measured in depending on extraction time 1, 2, 3, and 4 min (29.07, 52.39, 52.45, and 88.35 mg/g, respectively).

• Natural Product Sciences
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• v.24 no.3
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• pp.199-205
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• 2018

To determine the optimum extraction conditions that give the highest yield of isoquercitrin and caffeic acid from Aster scaber, the effects of four extraction variables (solvent concentrations, extraction time, number of repeated extraction, and solvent volumes) on isoquercitrin and caffeic acid yield was examined via HPLC-UV. Our results showed that the highest extract and isoquercitrin yield were observed when A. scaber was extracted with 450 mL distilled water for 8 hr repeatedly for three times. In case of caffeic acid, the content was higher in the two repeated extracts. Also, content analysis of isoquercitrin in Aster species was performed in which A. fastigiatus, A. ageratoides, and A. scaber exhibited the highest isoquercitrin content at 6.39, 5.68, and 2.79 mg/g extract, respectively. In case of caffeic acid, the highest content of A. scaber and A. glehni was 0.64 and 0.56 mg/g extract, respectively. This study reports an optimized method for extraction of isoquercitrin and caffeic acid from A. scaber and evaluates potential sources of the compounds.

• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.294-299
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• 2014

The simultaneous determination of platyphylloside, aceroside and betulin was established for the quality control of Betula platyphylla bark using a high performance liquid chromatography and diode-array UV/Vis detector (HPLC-DAD). Separation and quantification were successfully achieved with a INNO C18 column ($5{\mu}m$, 4.6 mm $I.D.{\times}150mm$) by gradient elution of a mixture of methanol and water at a flow rate of 1.0 ml/min. Validation of the developed method was performed by various factor such as linearity, specificity, precision, accuracy, system suitability and stability. This method was successfully applied to the determination of contents of platyphylloside, aceroside VIII and betulin in three batches of Betula platyphylla bark extract. These results suggest that the developed HPLC method is simple, effective and could be utilized as a quality control method for Betula platyphylla bark products.

• Korean Journal of Food Science and Technology
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• v.18 no.6
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• pp.475-478
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• 1986

RP-HPLC (Reverse phase-high performance liquid chromatography) assay which was introduced to measure quantitatively the amount of 4-methylthio-3-butenyl isothiocyanate in the radish root, proved to be convenient, accurate and reproducible, showing a good linearity between 10 n moles/ml and 120 n moles/ml (r=0.9997). The results of this assay showed that while the isohtiocyanate was hydrolyzed slowly in the basic medium, it decomposed rapidly in the acidic aqueous medium. On the other hand, the isothiocyanate was relatively stable in the organic solvent (65% acetonitrile). Also, it was found that intact root of Korean radish contain 210-420 ${\mu}moles/100g$, based on the measurement with radish homogenate (pH 8.5, 1 min).

• Analytical Science and Technology
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• v.7 no.3
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• pp.421-425
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• 1994

A micro-high performance liquid chromatography(Micro-HPLC) techniquie with solid phase extraction was reported which detected carbendazim and carbaryl at picogram levels. They were separated on microbore packed $C_{18}$ column($1.0mm\;I.\;D{\times}150mm$, $d_f=5{\mu}m$) using a 50% methanol mobile phase and detected at UV 220nm(${\alpha}=2.94$, $R_s=4.71$), while they were not resolved on analtical HPLC system(${\alpha}=1.27$, $R_s=0.76$). The detection thresholds of carbendazim and carbaryl were 0.5ng and 0.1ng on Micro-HPLC, therefore Micro-HPLC system was 20~40 told more sensitive than anayltical HPLC system. Sep-Pak $C_{18}$ catridge was found to be efficient in enriching carbendazim and carbaryl from dilute aqueous solution with 97.0% and 97.8% recoveries of them. The Sep-Pak $C_{18}$ catridge followed by the Micro-HPLC had been applied to the quantitative analysis of carbendazim and carbaryl in spiked juices and a commercial drinking water.

• Journal of Nutrition and Health
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• v.37 no.1
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• pp.45-51
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• 2004

In this study, isoflavone (genistein, genistin, daidzein, daidzin) contents in various parts of twelve soybean cultivars and three soy sprouts were determined by high performance liquid chromatography with UV detector. Three cultivars of soybean were selected and cultured in the lab to produce sprout for five days. Total isoflavone (Total IF) varied greatly among differnt breeds of soybean in range of 99 - 649.9 $\mu\textrm{g}$/g and 522.3 - 1,277.7 $\mu\textrm{g}$/g respectively, domestic and foreign cultivars. There were greatly difference in total IF of various parts of the soybean sprouts. Sprout from the Myunjunamul-kong appeared to have 69% genistein and 22% genistin in head part, and 30% and 62% of daidzin and daidzein, respectively, in root. Meanwhile, the sprouts from Junjori contains most (84%) of daidzein in its root. Sprout from chinese black-soybean had the largest amount of genistein among the sprouts but, there were no differences in the average genistein content between three selected black and non-black soys. The glycosidic form of IF were dominant compared to aglycone forms both in soybean and sprouts by 24 times and 12 times, respectively, suggesting that during the sprouts cultivation glycosidic forms could change to aglycone forms. There are no difference in total content between genistein + genistin and daidzein + daidzin in soy and soy sprout. Therfore, considering the total IF contents, the intake of 1 soy sprout is similer to 1.5 times as soybean.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.572-577
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• 2000

The effects of ibuprofen on bioavailability of ciprofloxacin were studied in rabbits. Animals were divided into three groups ; group A received 60 mg/kg of ciprofloxacin; group B and C received 60 mg/kg of ciprofloxacin with 60 and 240 mg/kg of ibuprofen, respectively. Ciprofloxacin and ibuprofen were given by single oral administration. Serum concentrations of ciprofloxacin were measured by high performance liquid chromatography with UV detector and pharmacokinetic parameters were calculated. Area under the serum concentrations versus time curve (${\pm}\;S.E.$) of ciprofloxacin were decreased in group B and C compared with group A ($12.26\;{\pm}\;0.94$ and $12.57\;{\pm}\;0.94$ vs. $15.71\;{\pm}\;1.06\;{\mu}g{\cdot}hr/ml$, p<0.05), whereas total clearances were increased ($1.81\;{\pm}\;0.13$ and $1.76\;{\pm}\;0.12$ vs. $1.40\;{\pm}\;0.09\;l/hr/kg$, p<0.05). No significant differances in these parameters were observed between group B and C. Relative bio-availability of group B and C to group A were 78 and 80%, respectively. These results suggest that the coadministration of ibuprofen with ciprofloxacin may reduce the bioavailability of ciprofloxacin.

• KSBB Journal
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• v.23 no.1
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• pp.96-100
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• 2008

In this work, we describes analysis of the antioxidant potential of Korean green tea phenolics using an high-performance liquid chromatography (HPLC) on-line $ABTS^{+}$ antioxidant screening method. In conjunction with the analysis of their 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging ability, the extraction of catechine compounds from Korean green tea were performed by various temperature and time. The optimum operating conditions were experimentally determined to analyze the catechine compounds in the pretreatment extracts. From the results, the extraction temperature $60^{\circ}C$, time 3 min was selected as an optimal antioxidant activity condition. The analysis by $C_{18}$ column was performed, the flow rate of mobile phase and UV wavelength was fixed at 1.0 ml/min and 254 nm, respectively. the mobile phase was composed from acetonitrile and water, and the gradient elution mode were applied.

• Journal of Pharmaceutical Investigation
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• v.22 no.1
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• pp.63-68
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• 1992

An HPLC procedure with UV detection has been developed for the quantitation of flurbiprofen released into isopropyl myristate used as the receptor phase in an in vitro membraneless drug diffusion cell. The drug and the internal standard (oxaprozin) were extracted from isopropyl myristate with a mixture of dimethylsulfoxide:methanol:water (2:1:1) and quantitated using a reverse phase $C_{18}$ column. The chromatograms were completely free from interfering peaks, and the relative retention times of flurbiprofen and the internal standard were 4.9 and 6.8 min, respectively. Calibration plots were linear over the concentration range of $1-200\;{\mu}g/ml$ of flurbiprofen with correlation coefficients, all higher than 0.99. The mean intra-day precision and accuracy among three replicate sets of the assay in a day were 4.26 and 4.52%, respectively, whereas the mean inter-day precision and accuracy were 3.35 and 3.64%, respectively. The mean recovery of the drug was 92.5% over the calibration range. The method was simple, reliable and accurate for the quantitation of flurbiprofen in unpurified isopropyl myristate.