• Korean Journal of Pharmacognosy
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• v.45 no.4
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• pp.338-345
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• 2014

HPL-4 is a new herbal formulation developed for the treatment of osteoarthritis. In this study, we took HPL-4 to develop a method for simultaneous determination of nine marker compounds (protocatechuic acid, chlorogenic acid, liriodendrin, nodakenin, ${\beta}$-$\small{D}$-(3-O-sinapoyl)frucofuranosyl-${\alpha}$-$\small{D}$-(6-O-sinapoyl)glucopyranoside, quercitrin, 6-gingerol, decursin and decursinol angelate) present in the formulation. The analytes were separated by UPLC system consisting of diode array detector at 205 nm and RP-amide column, and solvent system of $ACN/0.1%H_3PO_4$. Analytical method was validated to evaluate its linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. All standards showed good linearity ($R^2$ >0.99) in the rage of $0.25-400.0{\mu}g/mL$. The LOD and LOQ were within the range of 0.021-0.148 and $0.070-0.448{\mu}g/mL$, respectively. Intra- and inter-day precision was less than RSD 4.0% and the accuracy was range from 92.00-104.81% with RSD<4.2%. The results suggest that the developed UPLC method is precise, accurate and effective, and could be applied for quality control of HPL-4 formulation.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.513-518
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• 2005

Capillary electrophoresis (CE) method was developed to determine (+)-catechin and (-)-epicatechin contents in grape seed ethanol extract. CE separation was achieved using 100 mM phosphate and borate buffer at pH 6.0 as background electrolyte and fused silica capillary with 50 microns x 375 microns O.D. (effective length 20.0cm) maintained at $25^{\circ}C$. The applied voltage was 10kV, and detection was performed by DAD at 210 nm, Two catechins were well separated within 6 min with repeatability of <0.8% RSD for migration time and <2.0% RSD for peak area, and correlation coefficients higher than 0.994 were obtained from 58.0 to 174.0 mg/L with detection limit of 0.035 mg/L. Separated compounds were successfully determined. CE method was easy to handle and showed good reproducibility. CE method was compared with conventional coloring and HPLC methods, and main advantages of CE method were low amount of sample required, simple pre-sample treatment, good recovery rate, and short analysis time.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.177-182
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• 2012

A new composition of standardized Scutellariae Radix extract (HPO12) was developed for treatment of Alzheimer's disease. For the preclinical pharmacokinetic study of HPO12, a rapid, sensitive, and selective LCMS/MS method was developed and validated for the simultaneous determination of 4 bioactive compounds, baicalein, baicalin, wogonin, and wogonoside. After extraction with ethylacetate, chromatographic analysis was performed on a Thermo $C_{18}$ column ($150mm{\times}2.1mm$, $3{\mu}m$) with a mobile phase consisting of 0.1% formic acid (A) and 0.1% formic acid in 95% acetonitrile (B) by using gradient elution at a flow rate of $250{\mu}L/min$. Analytes introduced to a mass spectrometer were monitored by multiple reaction monitoring (MRM) in positive ion mode. Using $25{\mu}L$ of plasma sample, the method was validated over the following concentration ranges: 25-5000 ng/mL for baicalein, 20-40000 ng/mL for baicalin, 1-1000 ng/mL for wogonin, and 5-10000 ng/mL for wogonoside. The intra- and inter-day precision and accuracy of the quality control samples at the 4 concentrations showed $\leq$ 13.7% relative standard deviation (RSD) and 86.6-105.5% accuracy. The method was successfully applied to determine the concentrations of baicalein, baicalin, wogonin, and wogonoside in rat plasma after intraperitoneal and oral administrations of HPO12.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3055-3060
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• 2012

A simple, rapid and sensitive spectrofluorometric method was developed for the determination of folic acid (FA), based on its quenching effect on the fluorescence intensity of enoxacin (ENX)-europium ($Eu^{3+}$) complex as a fluorescent probe. Fluorometric interaction between ENX-$Eu^{3+}$ complex and FA was studied using UV-visible and fluorescence spectroscopy. The quenched fluorescence intensity at an emission wavelength of 614 nm was proportional to the concentration of FA. Optimum conditions for the determination of FA were investigated. Under optimal conditions, the reduced fluorescence intensity at 614 nm was responded linearly with the concentration of FA. The linearity was maintained in the range of $1.25{\times}10^{-9}$ to $1.50{\times}10^{-7}$ M (R = 0.9986) with the limit of detection ($3S_b/m$) (where $S_b$ is the standard deviation of blank and m is the slop of linear calibration curve) of $6.94{\times}10^{-10}$ M. The relative standard deviation (RSD) for 9 repeated measurements of $1.0{\times}10^{-9}$ M FA was 1.42%. This method was simple, cost effective, and relatively free of interference from coexisting substances. Successful determinations of FA in pharmaceutical formulation and biological samples with the developed method were demonstrated.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.622-628
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• 2010

In this study, Solid-phase microextraction (SPME) with GC/FID was studied as a possible alternative to liquid-liquid extraction for the analysis of BTEX and MTBE. Experimental parameters affecting the SPME process (such as kind of fibers, adsorption time, desorption time, volume ratio of sample to headspace, salt addition, and magnetic stirring) were optimized. Experimental parameters such as CAR/PDMS, adsorption time of 20 min, desorption time of 5 min at $250^{\circ}C$, headspace volume of 50 mL, sodium chloride (NaCl) concentration of 25% combined with magnetic stirring were selected in optimal experimental conditions for analysis of BTEX and MTBE. The general affinity of analytes to CAR/PDMS fiber was high in the order p-Xylene>Toluene>Ethylbenzene>MTBE>Benzene. The linearity of $R^2$ for BTEX and MTBE was from 0.970 to 0.999 when analyte concentration ranges from $30{\mu}g/L$ to $500{\mu}g/L$, respectively. The relative standard deviation (% RSD) were from 2.5% to 3.2% for concentration of $100{\mu}g/L$ (n=5), respectively. Finally, the limited of detection (LOD) observed in our study for BTEX and MTBE were from $7.5{\mu}g/L$ to $15{\mu}g/L$, respectively.

• Korean Journal of Pharmacognosy
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• v.40 no.4
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• pp.298-302
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• 2009

Samultang is one of traditional medicine composed of Paeonia lactiflora, Angelica gigas, Rehmannia glutinosa and Cnidium officinale. To develop simultaneous determination of paeoniflorin, decursin and 5-HMF in Samultang, a high performance liquid chromatography with diode array detector was used. To separate three marker components, Dionex $C_{18}$ column (5 ${\mu}m$, 120 ${\AA}$, 4.6 mm${\times}$150 mm) was used with a gradient elution system of water and methanol. UV wavelength of detector set at 230 nm and 280 nm. This method was validated by linearity, precision test and recovery test. Calibration curves of three standard components were showed good linear regression ($R^2$>0.9973). LOD and LOQ ranged from 0.08 ${\mu}g$/ml to 0.38 ${\mu}g$/ml and 0.25 ${\mu}g$/ml to 1.16 ${\mu}g$/ml, respectively. The relative standard deviations (RSDs) of data of the inter-day and intra-day experiments were less than 0.54% and 0.89%, respectively. The measured results of recovery test were varied from 93.36 to 107.79 with RSD values 0.01~1.45%. The established method was applied for separation of bio-conversion Samultang sample and compared with control sample.

• Environmental Engineering Research
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• v.25 no.4
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• pp.579-587
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• 2020

Novel silane grafted bentonite was obtained using the natural bentonite as precursor material. The material which is termed as nanocomposite was characterized by the Fourier Transform Infra-red (FT-IR) and X-ray diffraction (XRD) methods. The surface imaging and elemental mapping was performed using Scanning Electron Microscopic (SEM/EDX) technique. The electroanalytical studies were performed using the nanocomposite electrode. The electroactive surface area of nanocomposite electrode was significantly increased than the pristine bentonite or bare carbon paste based working electrode. The impedance spectroscopic studies were conducted to simulate the equivalent circuit and Nyquist plots were drawn for the carbon paste electrode and nanocomposite electrodes. A single step oxidation/reduction process occurred for As(III) having ΔE value 0.36 V at pH 2.0. The anodic stripping voltammetry was performed for concentration dependence studies of As(III) (0.5 to 20.0 ㎍/L) and reasonably a good linear relationship was obtained. The detection limit of the As(III) detection was calculated as 0.00360±0.00002 ㎍/L having with observed relative standard deviations (RSD) less than 4%. The presence of several cations and anions has not affected the detection of As(III) however, the presence of Cu(II) and Mn(II) affected the detection of As(III). The selectivity of As(III) was achieved using the Tlawng river water sample spiked with As(III).

• Analytical Science and Technology
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• v.30 no.6
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• pp.379-389
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• 2017

In this study, we set up an analytical method that can be used for rapid and accurate determination of representative isoquinoline alkaloids in medicinal plants using UPLC-ESI-Q-TOF MS (ultra pressure liquid chromatography-electrospray ionization-quadrupole-time-of-flight mass spectrometry). The compounds were eluted on a C18 column with 0.1 % formic acid and acetonitrile, and separated with good resolution within 13 min. Each of the separated components was characterized by precursor ions (generated by ESI-Q-TOF) and fragment ions (produced by collision-induced dissociation, CID), which were used as a reliable database. We also performed method validation: analytes showed excellent linearity ($R^2$, 0.9971-0.9996), LOD (5-25 ng/mL), LOQ (17-82 ng/mL), accuracy (91.6-97.4 %) as well as intra- and inter-day precisions (RSD, 1.8-3.2 %). In the analysis of Chelidonium majus L., magnoflorine, coptisine, sanguinarine, berberine and palmatine were detected by matching retention times and characteristic fragment ion patterns of reference standards. We also confirmed that, among the quantified components, coptisine was present in the highest quantity. Furthermore, alkaloid profiling was carried out by analyzing the fragment ion patterns corresponding to peaks of unknown components. In this manner, protopine, chelidonine, stylopine, dihydroberberine, canadine, and nitidine were tentatively identified. We also proposed the molecular structure of the fragment ions that appear in the mass spectrum. Therefore, we concluded that our suggested method for the determination of major isoquinoline alkaloids by UPLC-Q-TOF can be useful not only for quality control, but also for rapid and accurate investigation of phytochemical constituents of medicinal plants.

• Korean Journal of Pharmacognosy
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• v.51 no.3
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• pp.217-221
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• 2020

Cirsium japonicum var. maackii (CM) has been used to treat certain medical conditions such as hemorrhage, hepatitis, and hypertension. Cirsimaritin was previously found as the major flavonoid in CM and is said to contribute to its pharmacological effects. There are currently no reports detailing the qualitative and quantitative detection of phytochemical indicators in the aerial parts of CM. Therefore, we developed a method to rapidly identify and quantify cirsimaritin in CM using HPLC/UV, and we optimized and validated this analytical method. The results showed good linearity in the concentration range tested (0.25-0.015 mg/mL, r² ≥ 0.9999), accuracy (93.9-111.3%), and precision (RSD ≤ 0.59%). The developed method can therefore be used for the rapid evaluation of cirsimaritin in CM.

• Natural Product Sciences
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• v.26 no.1
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• pp.64-70
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• 2020

Citrus junos seeds (CS) have been traditionally used for the treatment of cancer and neuralgia. They are also used to manufacture edible oil and cosmetic perfume. A large amount of CS shells without oil (CSS) are discarded after the oil in CS is used as foods or herbal remedy. To efficiently utilize CSS as a by-products, it needs to be studied through chemical analysis. Therefore, we developed an ultra-performance liquid chromatography (UPLC)-diode array detection (DAD) method for simultaneous determination and quantitative analysis of five components (two flavonoids and threes limonoids) in CSS. A Waters Acquity UPLC HSS T3 column C18 (2.1 × 100 mm, 1.8 ㎛) was used for this separation. It was maintained at 40 ℃. The mobile phase used for the analysis was distilled water and acetonitrile with gradient elution. To identify the quantity of the five components, a mass spectrometer (MS) with an electrospray ionization (ESI) source was used. The regression equation showed great linearity, with correlation coefficient ≥ 0.9912. Limits of detection (LOD) and limits of quantification (LOQ) of the five compounds were 0.09 - 0.13 and 0.26 - 0.38 ㎍/mL, respectively. Recoveries of extraction ranged from 97.45% to 101.91%. Relative standard deviation (RSD) values of intra- and inter-day precision were 0.06 - 1.15% and 0.19 - 0.25%, respectively. This UPLC-DAD method can be validated to simultaneously analyze quantities of marker flavonoids and limonoids in CSS.