• The Journal of Korean Medicine
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• v.31 no.6
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• pp.8-15
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• 2010

Objectives: We investigated to develop and validate HPLC-PDA methods for simultaneous determination of eight constituents in Galgeun-tang (GGT). Methods: Reverse-phase chromatography using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array (PDA) detection at 230 nm, 254 nm, and 280 nm, were used for quantification of the eight marker components of GGT. The mobile phase using a gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. Results: Calibration curves were acquired with $r^2$ > 0.9999, and the relative standard deviation (RSD) values (%) for intra- and inter-day precision were less than 3.0%. The recovery rate of each component was in the range of 87.33-101.38%, with an RSD less than 7.0%. The contents of the eight components in GGT were 1.98-12.17 mg/g. Conclusions: The established method will be applied for the quantification of marker components in GGT.

• Herbal Formula Science
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• v.18 no.1
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• pp.95-103
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• 2010

Objectives : To develop and validate HPLC-PDA methods for simultaneous determination of seven constituents in Samsoeum(SSE). Methods : Reverse-phase chromatography using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array(PDA) detection at 254 and 280 nm, were used for quantification of the seven marker components of SSE. The mobile phase using a gradient flow consisted of two solvent systems. Solvent A was 1.0% (v/v) aqueous acetic acid and solvent B was acetonitrile with 1.0% (v/v) acetic acid. Results : Calibration curves were acquired with $r^2$>0.9997, and the relative standard deviation (RSD) values (%) for intra- and inter-day precision were less than 3.0%. The recovery rate of each compound was in the range of 100.07-112.65%, with an RSD less than 4.0%. The contents of seven compounds in SSE were 1.24-10.53 mg/g. Conclusions : The established method will be helpful to improve quality control of SSE.

• Korean Journal of Veterinary Service
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• v.26 no.2
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• pp.157-162
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• 2003

This stud was attempted to detect six benzimidazoles[thiabendazole(TBZ), oxfendazole(OFZ), mebendazole(MBZ), flubendazole(FLBZ), albendazole(ABZ), and febendazole(FBZ)] in eggs using high performance liquid chromatography(HPLC) with photodiode array detector(DAD) simultaneously. The eluates were determined by HPLC on a waters X-Terra$^{TM}\;C_{18}$ reverse-phase column($4.6{\times}250nm,\;5{\mu}m$) with DAD at 295nm. The mobile phase was 0.04M ammonium phosphate(pH 7.5)/ACN(62.28 v/v) run isocratically. The calibration curves were linear(r>0.999) for six benzimidazoles. Average recovery rate from eggs were 94.54% for TBZ, 97.71% for OFZ, 88.82% for MBZ, 93.71% for FLBZ, 78.61% for ABZ, and 75.09% for FBZ, respectively. The limits of detection and quantification were 2.27ppb, 3.88 for TBZ, 9.34ppb, 15.61ppb for OFZ, 28.53ppb, 45.15ppb for MBZ, 27.39ppb, 40.95ppb for FBZ, 8.61ppb, 13.95ppb for ABZ and 12.79ppb, 22.34ppb for FBZ, respectively.

• Food Science and Preservation
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• v.4 no.2
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• pp.181-187
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• 1997

New HPLC method was developed for determination of some flavonoids such as naringin, hesperidin, neohesperidin, rutin, quercitrin, naringenin, hesperetin and apigenin and their contents in citrus juice and citrus peel from citrus varieties Brown in Cheju. Detection was at 280nm and reverse phase ${\mu}$-Bondapak C-18 column was used. Water/methanol/acetic acid as the mobile phase was better than water/acetonitrile/acetic acid. Flavonoids were more stable in 20% n,n-dimethylformamide in methanol(20% DMF) than methanol and pH 12 adjusted by 1N-sodium hydroxide solution. Standard flavonoid solutions were injected three times consecutively and the reproduciability was 0.236 to 3.550%, Correlation coefficient of the calibration curve was 0.9946 to 0.9999. The exiraction efficiency of hesperidin from citrus peel was evaluated with different extraction method such as reflux, ultra-sonicating method, using three solvents (aqueous solutions with pH12 adjusted by 1N-sodium hydroxide, methanol and 20% DMF), respectively. The reflux for 4 hour in 20% DMF was the most efficient of the tested methods and solvents, and recovery percentage were 78.0∼130.0%. Flavonoids were determined in citrus juice. Naringin was 68.2mg/100$m\ell$ in Natsudaidai, Hesperidin were 85.6mg/100$m\ell$ in Sankyool and Neohesperidin was 25.3mg/100$m\ell$ in Dangyooja. Flavonoids were determined in citrus peel. Naringin was 110mg/g in Dangyooja, Hesperidin was 242mg/g in Hungjin and Neohesperidin was 87.9mg/g in Dangyooja.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.300-306
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• 2000

In the present studies, we assessed the stability of active components and toxicological safety of irradiated Angelica gigas Nakai(Danggui). In order to confirm the stability of active components in the ${\gamma}$-irradiated roots of Danggui, the quantitative analysis of decursin and decursinol angelate of ${\gamma}$-irradiated sample was carried out by high performance liquid chromatographic (HPLC) methods using reverse phase columns and normal phase columns. From the root of Danggui, decursin and decursinol angelate were isolated by a silica gel column chromatography(toluene : ether (1 : 1), Hexane : EtOAc(15 : 1)). And then the structures were confirmed in the 1H and 13C-NMR analysis. The HPLC chromatograms of decursin and decursinol angelate in ${\gamma}$-irradiated Danggui were similar with those of non-irradiated sample. In the examination of in vitro genotoxicity of the water extract from ${\gamma}$-irradiated Danggui using Salmonella reversion assay(Ames test) and micronucleus test in Chinese hamster ovary (CHO) cells, mutagenicity was not exhibited in the two assays with or without metabolic activation. These resutls suggest that active components in the ${\gamma}$-irradiated Danggui should be stable and that the safety of ${\gamma}$-irradiated Danggui could be revealed in further test in vivo.

• Analytical Science and Technology
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• v.36 no.4
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• pp.152-160
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• 2023

Adenosine and cordycepin are bioactive compounds with health benefits. Therefore, both substances are often used to assess the quality of Cordyceps products. Optimization and validation of the HPLC/DAD method for determining two nucleosides were studied. The samples were prepared using an ultrasound-assisted extraction (ultrasonic bath). The result was optimal conditions for aqueous extraction, an extraction time of 35 min, and an extraction temperature of 40 ℃. The Chromatographic separation was achieved using a reverse phase column (InfinityLab Poroshell 120 EC-C18, 4.6 × 250 mm, 2.7 ㎛) at 30 ℃ with a mobile phase gradient elution of water and methanol at a flow rate of 0.7 mL/min. The eluents were monitored via a diode array detector at 260 nm. Two nucleosides were separated by less than 12 min after injection. The developed method was found to be excellent linear (r² > 0.9999), accurate (% recovery 95.34-98.51), and precise (% relative standard deviation < 2.0). The limit of detection (LOD) and quantification (LOQ) were 0.45 and 1.38 mg/mL for adenosine and 0.47 and 1.43 mg/mL for cordycepin, respectively. This method was satisfactory for simultaneously quantitating two nucleoside contents, which were used to evaluate Cordyceps products.

• Journal of the Korean Applied Science and Technology
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• v.14 no.1
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• pp.61-76
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• 1997

Triacylglycerols of the seeds of Ginkgo biloba have been resolved by high-performace liquid chromatography(HPLC} in the silver-ion and reverse-phase modes. The fatty acids were identified by a combination of capillary gas chromatography and gas-chromatography /mass spectrometry as the methyl and /or picolinyl ester. The main components are $C_{18:2{\omega}6}$(39.0mol%), $C_{18:1{\omega}7}$(asclepic acid 21.5mol%), and $C_{18:1{\omega}9}$(oleic acid, 13.8mol%). Considerable amounts of unusual acid such as $C_{20:3{\Delta}^{5,11,14}$ (5.7mol%), $C_{18:2{\Delta}^{5,9}$(2.8mol%), and $C_{18:3}{\Delta}^{5,9,12}$(1.6mol%), were checked. In addition, an anteiso-branched fatty acid, 14-methylhexadecanoic acid, was also present as a minor component(0.9 mol%). The triacylglycerols were separated into 17 fractions by reverse-phase HPLC, and the fractionation was achieved according to the partition numnber(PN) in which a ${\Delta}^5$-non methylene interrupted double bond($^5$-NMDB) showed different behaviour from a methylene interrupted double bond in a molecule with a given cahinlength. Silver-ion HPLC exhibited excellent resolution in which fractions(23 fractions) were resolved on the basis of the number and configuration of double bonds. In this instance, the strength of interaction of a ${\Delta}^5$-NMDB system with silver ions seemed to be weaker than a methylene interrupted double bond system. The principal triacylglycerol species are as follows ; $(C_{18:2{\omega}6)2}/C_{18:1{\omega}7}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$, $C_{16:1{\omega}7}/C_{18:1{\omega}9}/C_{20:3}{\Delta}^{5,11,14}$, $C_{16:1{\omega}7}/C_{18:1{\omega}7}/C_{20:3}{\Delta}^{5,11,14}$, $C_{18:1{\omega}9}/C_{18:1{\omega}7}/C_{18:2{\omega}6}$, $C_{18:1{\omega}9}/C_{18:2}{\Delta}^{5,5}/C_{20:3}{\Delta}^{5,11,14}$, $(C_{18:1{\omega}7)2}/C_{18:2{\omega}6}$ and $(C_{18:1{\omega}9)2}/C_{18:2{\omega}6}$, while simple triacylglycerols without $C_{18:2{\omega}6})_3$ were not present. Stereospecific analysis showed that fatty acids with ${\Delta}^5$-NMDB system and saturated chains were predominantly located at the site of sn-3 carbon of glycerol backbones. It is evident that there is asymmetry in the distribution of fatty acids in the TG molecules of Ginkgo nut oils.

• Journal of Pharmaceutical Investigation
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• v.21 no.3
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• pp.171-177
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• 1991

A reverse-phase, ion-pair high performance liquid chromatographic (HPLC) method for the simultaneous quantative determination of pyridostigmine and its hydrolytic product, 3-hydroxy-N-methylpyridinium (HMP), is descrihed, The assay of pyridostigmine and HMP was linear in the range of amount from 24 to 60 mg/tablet and from 2.4 to 12.0 mg/tablet, respectively, with coefficient of variation (C.V.) of 0.05-0.12% (n=7) and 0.25-0.52% (n=5), respectively, and applicable conveniently even in the case of the mixture of pyridostigmine and HMP. Meanwhile, the conventional UV method gave inaccurate results for the aged pyridostigmine tablets. In the extraction of pyridostigmine from tablets prior to be assayed by HPLC, methanol was found to be more effective than ethanol or distilled water. Multiple extraction (four times) with methanol resulted in the full recovery of pyridostigmine, whereas ethanol gave 95% recovery even after four times extraction. Based on these results. the present method would be very useful for the accurate determination of pyridostigmine in the aged pyridostigmine tablets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.59-65
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• 2006

Fluoroquinolones are the most common group of antibacterial agents currently used in the Korean aquaculture industry, and use of these agents has been increasing steadily. High performance liquid chromatography (HPLC) with fluorescence detection was used for the simultaneous determination of five fluoroquinolones in fish and shellfish: ofloxacin (OFL), pefloxacin (PEF), norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENRO). Fish and shellfish muscle was homogenized, and protein, lipid, and low molecular weight pigments were then excluded from the homogenate. The final eluates were analyzed by HPLC equipped with a Shiseido UG-120 type C18 reverse-phase column ($4.6{\times}250 mm$, $5{\mu}m$) and a fluorescence detector (excitation at 280 nm, emission at 450 nm). The mobile phase was 0.1 M phosphoric acid and acetonitrile solution (91:9, v/v) and tetrahydrofuran (THF) was added to it at a rate of 5 mL per a liter of the mobile phase. Adequate chromatography separation was obtained using the above method. Average recoveries of fortified samples at levels from 0.05 to 0.5 mg/kg were $72.3{\pm}2.5-84.5{\pm}1.2%$ for OFL, $82.7{\pm}3.3- 109.3{\pm}7.5%$ for NOR, $85.3{\pm}6.6-116.0{\pm}7.9%$ for PEF, $76.0{\pm}4.3-109.3{\pm}12.4%$ for CIP, and $78.7{\pm}5.9-100.0{\pm}9.8%$ for ENRO. The limit of detection of OFL was $5{\mu}g/L$, the others were $1{\mu}g/L$. We concluded that the new analytical method was suitable for the determination of fluoroquinolones in fish and shellfish.

• Archives of Pharmacal Research
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• v.29 no.4
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• pp.339-342
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• 2006

A simple high performance liquid chromatographic (HPLC) method was developed for the determination of tolperisone in human plasma. Tolperisone and internal standard (chlorphenesin) were isolated from 1 mL of plasma using 8 mL of dichlormethane. The organic phase was collected and evaporated under nitrogen gas. The residue was then reconstituted with 300 mL aliquot of mobile phase and a 100 mL aliquot was injected onto the $C_{18}$ reverse-phased column. The mobile phase, $45\%$ methanol containing $1\%$ glacial acetic acid and $0.05\%$ 1-hexanesulfonic acid was run at a flow rate of 1 mL/min. The column effluent was monitored using UV detector at 260 nm. The retention times for tolperisone and the internal standard were approximately 7.1 and 8.4 min, respectively. The standard curve was linear with minimal intra-day and inter-day variability. The quantification limit of tolperisone in human plasma was 10 ng/ mL. The proposed method has been applied to the determination of pharmacokinetic profile of tolperisone in Koreans. The T max of tolperisone in Koreans $(0.94{\pm}0.42\;h)$ was not significantly differ from that reported in Europeans (0.5-1 h), but the mean half-life in Koreans $(1.14{\pm}0.27\;h)$ was shorter than that in Europeans $(2.56{\pm}0.2\;h)$. The proposed HPLC method is simple, accurate, reproducible and suitable for pharmacokinetic study of tolperisone.