• YAKHAK HOEJI
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• v.31 no.5
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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.

• Journal of Food Hygiene and Safety
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• v.2 no.3
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• pp.89-95
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• 1987

This studies was performed to investigate the quality control of Pueraria RadiI tea. Experimental subjects were 8 kinds of tea and wet and dry Pueraria RadiI which were collected from the Seoul area. For standards, Daidzein and Daidzin were isolated from Pueraria Radix. Analysis method was carried out by HPLC using ${\mu}-Bondapark{\;}C_{18}$ column and UV 254 nm detector. Samples were extracted with methanol by Cold method (at room temperature for 24 hours) and Hot extraction method (at $^{\circ}C$ for 4 hours) Pueraria radix contained 0.08% Daidzein and 0.66% Daidzin Most of the Pueraria Radix tea contained extract of Pueraria Radix less than the labled amounts listed.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.13-17
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• 2021

Qantitative analysis of six compounds: (+)-catechin, benzoic acid, gallic acid methyl ester, paeonol, paeoniflorin, and albiflorin from Paeonia lactiflora extracts was performed using high-performance liquid chromatography and an ultraviolet (UV) detector, following different extraction methods. A reverse-phase column was used in a gradient elution system, and UV detection was performed at 280 nm. The results showed that the quantity of paeoniflorin was the highest in ethanol and water extracts (73.89 and 57.87 mg/g, respectively) among the six compounds. This study contributes a good analysis method for the contents of P. lactiflora and would be propitious for developing medicines and functional foods.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.453-461
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• 1993

Detection method was developed using a simply designed photochemical reactor made of teflon coil and low pressure mercury lamp. This method of UV photolysis of analytes followed by UV, fluorescence and electrochemical detection was found to be useful for four thiocarbamates. Analytes eluting from the column are irradiated with a high flux of 254 nm UV light, so that they change to either fluorescent active forms or highly electrochemically sensitive products. Appling this technique to the UV detection, thiocarbamates were converted into long wavelength absorbing products upon UV irradiation. In fluorescence detector four thiocarbamates are not detected at nonirradiated condition but fluorescence signals of MPTC, CPTC photolysates are appeared after irradiation with UV light. The electrochemical detection for the determination of thiocarbamates was enhanced up to 5∼20 fold signal after UV irradiation, compared to that of the nonirradiated. The detection limit of thiocarbamates on electrochemical detector was 13.3∼0.02 ng under pH 7.0, ionic strength $0.5{\times}10^{-2}$ M, phosphate buffer solution. Adducts produced by reaction of photolysates and OPA-MERC in the reaction coil were monitored at 425 nm with fluorescence detector, and one of the photolysates was primary amine.

• 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.

• Journal of Pharmaceutical Investigation
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• v.22 no.4
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• pp.317-321
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• 1992

A high-performance liquid chromatographic (HPLC) method was developed for the determination of diltiazem (DTZ) and its major metabolite, deacetyldiltiazem (DAD), in rat plasma. DTZ, DAD and imipramine, the internal standard, were selectively fractionated from plasma on a $C_{18}$ reversedphase column $({\mu}-Bondapak,\;10\;{\mu}m\;silica,\;300{\times}3.9\;mm\;ID)$. The composition of the mobile phase was methanol: acetonitrile: 0.04 M ammonium bromide: triethylamine (40:24:36:0.06 in volume). The pH of the mobile phase of their method was lowered to 6.4. The eluents from the column were detected for DTZ and DAD using a UV detector at 237 nm. The recovery was >85% for DTZ and DAD, and average intra-day and inter-day coefficients of variation were <6% for DTZ and DAD at the concentration ranges of 20-1000 ng/ml. Detection limit of DTZ and DAD in plasma was 20 ng/ml with signal-to-noise ratio of 3. This method would be applicable to practical pharmacokinetic studies without detriment to the HPLC column.

• Journal of Food Hygiene and Safety
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• v.3 no.4
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• pp.203-209
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• 1988

This study was performed to develop the simple and rapid determination method of preservatives in Yogurt and Soybean.sauce. 1. The analytical method by HPLC system was as follow: The sample was diluted, centrifuged, filtered, if necessary, and analyzed by HPLC system with UV detector. 2. The analytical method by GLC system was as follow: The sample was extracted directly with ether, added cone. sulfuric acid to destroy emulsion and analyzed by the GLC system with FID. 3. The recovery rates of preservatives by the above methods were higher than 99.0 %. 4. Total running time for the above methods was less than 50 minutes. Especially, the running time for dilution method by HPLC system was one-third of that for GLC method.

• Korean Journal of Pharmacognosy
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• v.41 no.4
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• pp.323-327
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• 2010

A high performance liquid chromatographic (HPLC) method for the simultaneous determination of dictamine, obacunone and fraxinellone was established for the quality control of traditional herb Dictamnus dasycarpus cortex. Separation and quantification were successfully achieved with a Shiseido C18 column ($5\;{\mu}m$, 4.6 mm I.D. ${\times}$ 250 mm) by gradient elution of a mixture of methanol and water at a flow rate of 1.0 ml/min. The diode-array UV/Vis detector (DAD) was used for the detection and the wavelength for quantification was set at 236 nm. The presence of dictamine, obacunone and fraxinellone in this extract was ascertained by retention time, spiking with each authentic standard and UV spectrum. All three compounds showed good linearity ($r^2$ > 0.999) in relatively wide concentration ranges. The R.S.D. recovery of each compound was 101.0~103.7% with R.S.D. values less than 1.0%. This method was successfully applied to the determination of contents of dictamine, obacunone and fraxitnellone in three commercial products of D. dasycarpus cortex. These results suggest that the developed HPLC method is simple, effective and could be readily utilized as a quality control method for commercial products.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.571-577
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• 2012

This study was carried out to develop an analytical method for the determination of vitamin D in infant formula. Vitamin D was determined by column-switching high-performance liquid chromatography (HPLC) equipped with a reversed phase column and UV detector after saponification and extraction of the formula with an organic solvent. A preseparation column ($C_8$), focusing column ($C_{18}$), analytical column ($C_{18}$) and UV-Vis detector (254 nm) were used. The limits of detection (LOD) and the limits of quantification (LOQ) for vitamin D were estimated to be $1.51{\mu}g/kg$ and $4.95{\mu}g/kg$, respectively. The linearity, recovery, precision and accuracy of the analytical method for vitamin D were evaluated through the application of a SRM (Standard Reference Material) 1846 (National Institute of Standard & Technology, USA). The linearity of this method was calculated with a value of the coefficient of determination ($r^2$) ${\geq}0.9999$. The recovery of vitamin D was $85.20{\pm}3.00%$. The intra-assay precision for vitamin D was between $1.68{\pm}0.03%$ and $5.75{\pm}0.33%$, and the inter-assay precision for vitamin D ranged from $1.73{\pm}0.03%$ to $2.96{\pm}0.09%$. The intra-assay accuracy for vitamin D was between $100.03{\pm}2.77%$ and $102.01{\pm}0.59%$, and the inter-assay accuracy for vitamin D ranged from $99.00{\pm}1.53%$ to $102.01{\pm}3.04%$. The proposed method is optimal for the separation and quantification of vitamin D from infant formula.

• Journal of Preventive Veterinary Medicine
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• v.42 no.4
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• pp.171-176
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• 2018

A study of the tissue depletion of florfenicol (FFC) administered orally to pigs at a dose of 0.05 kg/ton feed for 7 days was performed. Sixteen healthy cross swine were administered with FFC. Four treated animals were arbitrarily selected to be sacrificed 1, 3 and 5 days after the end of treatment. FFC residue concentrations in muscle, liver, kidney, and fat were determined using high-performance liquid chromatography (HPLC) with ultraviolet photometric detector at 230 nm. The correlation coefficient ($R^2$) of the calibration curve for florfenicol amine (FFCa) was > 0.997 and the limits of detection and quantification were 0.012 and $0.040{\mu}g/mL$, respectively. Recovery rates in swine edible tissues ranged from 79.1 to 93.5%. In the FFC-treated group, FFC residues at 3 days post-treatment were below the maximum residue limits (MRLs) in muscle, kidney and fat, and those at 5 days post-administration were below the MRLs in all edible tissues. These results suggest that the withdrawal period of FFC after the drug treatment might be 5 days, which is a sufficient amount of time for reduction of the FFC residues below the MRLs in all edible tissues.