• KSBB Journal
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• v.30 no.4
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• pp.141-147
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• 2015

The convenient determination of methylsulfonylmethane (MSM) for a commercially available dietary supplement was developed using gas chromatography (GC)-flame ionization detector (FID). Chromatography was performed on a capillary column ($0.32mm\;I.D{\times}30m$, $0.25{\mu}m$) coated with dimethylpolysiloxane using diethylene glycol methyl ether as an internal standard. The performance characteristics of GC were evaluated in terms of selectivity, linearity, precision, accuracy, recovery, limit of detection (LOD) and limit of quantification (LOQ). The calibration curve was highly linear (the coefficient of determination: 0.9979) within the concentration range of $10.0{\sim}800.0{\mu}g/mL$ for MSM. The recoveries for three fortified concentrations were 96.7~97.1%, 96.6~97.3% and 96.8~97.2%, respectively. The LOD and LOQ of the method were $0.29{\mu}g/mL$ and $0.97{\mu}g/mL$, respectively. All obtained results were acceptable according to the guidelines of the Association of Official Analytical Chemists for dietary supplements. Thus, the validated analytical method using the GC-FID system is suitable for the determination of MSM in dietary supplement formulations for quality control.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.527-527
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• 2003

A high-performance liquid chromatographic method for the simultaneous quantitative analysis of DMDM hydantoin, sorbic acid, phenoxy ethanol in cosmetics was studied by using a X-terra C$\sub$18/ column and 0.75mM KH$_2$PO$_4$ in 0.85% sulfuric acid and methanol mixture(7:3) at 214nm. Calibration curves were found to be linear in the 20-100 $\mu\textrm{g}$/mL range (DMDM hydantoin), 50-250 $\mu\textrm{g}$/mL range (sorbic acid) and 10-50 $\mu\textrm{g}$/mL range (phenoxy ethanol). The result of recovery test were 96.6% ∼ 104.2%. This HPLC method can be applied quality control of cosmetics.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.137-137
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• 2021

The study of total phenol (TP) content from 700 rice varieties was evaluated using the UV-Vis spectrophotometric method. The calibration curve of serial diluted gallic acid as a standard of this study showed the acceptable performances (R² = 0.999, mean accuracy 90%) and the mean of % relative standard deviation (%RSD: 0.07%) within the range of 7.8 to 1000 ppm concentrations. The mean value of total phenol content from 700 rice varieties was 2723.15 ㎍/g ranged from 55.48 ㎍/g to 9922.23 ㎍/g and the mean %RSD was 2.5%. Furthermore, this study aim was to analyze and profile individual phenolic compounds in the rice genetic resources to construct an integrative database for development of new rice variety with high functionality for health and understanding of phenolics characteristics in the rice grain. Herein, we analyzed selected 100 rice varieties based on high TP content and identified total 15 phenolic compounds by LC-ESI-MS/MS. Among selected 100 rice genetic resources, the phenolic metabolites consisted of higher amount of flavonoid (catechin) and phenolic acid mainly protocatechuic acid. Further research of more selected rice genetic resources would be continued to provide for an integrative phenolics profile of different rice genetic resources.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1907-1914
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• 2010

A novel catalytic kinetic method is proposed for the determination of Se(IV), Se(VI) and total inorganic selenium in water based on the catalytic effect of Se(IV) on the reduction of bromate by p-nitrophenylhydrazine at pH 3.0. The generated bromine, $Br_2$ or $Cl_2$ plus $Br_2$ in 0.1 M NaCl (or NaBr) environment efficiently decolorized Calmagite and the reaction was monitored spectrophotometrically at 523 nm as a function of time. In this indicator reaction, bromide acted as an activator for the catalysis of selenium (IV) and a reducing agent for selenium (VI) at pH 3.0, which allowed the determination of total selenium. The fixed time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the calibration graph are linear in the range 1 - 35 ${\mu}gL^{-1}$ of Se(IV) for the fixed time method at $25^{\circ}C$. The detection limit based on statistical $3S_{blank}$/m-criterion was 0.215 ${\mu}gL^{-1}$ for the fixed time method (7 min). All of the variables that affect the sensitivity at 523 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se (IV) determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The RSDs for ten replicate measurements of 5, 15 and 25 ${\mu}gL^{-1}$ of Se(IV) and Se(VI) was changed between 2.1 - 4.85%. Analyses of a certified standard reference material (NIST SRM 1643e) for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. Se(IV), Se(VI) and total inorganic selenium in environmental water samples have been successfully determined by this method after selective reduction of Se(VI) to Se(IV).

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.67-72
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• 2012

The chemical characterization of water-soluble organic carbon in ash emitted from a coal combustion boiler has not been reported yet. A total of 5 ash samples were collected from the outlet of an electrostatic precipitator in a commercial 500 MW coal-fired power plant, with their chemical characteristics investigated. XAD7HP resin was used to quantify the hydrophilic and hydrophobic water-soluble organic carbons (WSOC), which are the fractions of WSOC that penetrate and remain on the resin column, respectively. Calibration results indicate that the hydrophilic fraction includes aliphatic dicarboxylic acids and carbonyls (<4 carbons), amines and saccharides, while the hydrophobic fraction includes aliphatic dicarboxylic acids (>4-5 carbons), phenols, aromatic acids, cyclic acid and humic acid. The average mass of the WSOC in the ash samples was found to depend on the bituminous coal type being burned, and ranged from 163 to 259 ${\mu}g$ C/g of ash, which corresponds to 59-96 mg C of WSOC/kg of coal combusted. The WSOC mass accounted for 0.02-0.03 wt% of the used ash sample mass. Based on the flow rate of flue gas produced from the combustion of the blended coals in the 500 MW coal combustion boiler, it was estimated that the WSOC particles were emitted to the atmosphere at flow rates of 4.6-7.2 g C/hr. The results also indicated that the hydrophilic WSOC fraction in the coal burned accounted for 64-82% of the total WSOC, which was 2-4 times greater than the mass of the hydrophobic WSOC fraction.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.2
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• pp.168-173
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• 2015

Bangpungtongseong-san(BPTSS, Fangfengtongsheng-san in Chineses) is a traditional herbal formula comprising 18 medicinal herbs. In the present study, we performed the simultaneous analysis for four compounds of BPTSS and examined anti-allergic effects in human keratinocytes and mouse splenocytes. The column for separation of four compounds was used Luna C18 column and maintained at 40℃. The mobile phase for gradient elution consisted of two solvent systems. The analysis was carried out at a flow rate of 1.0 mL/min with PDA detection at 254 and 280 nm. To evaluate production and expression of Th2 chemokines, ELISA and RT-PCR were conducted in tumor necrosis factor (TNF)-α and interferon (IFN)-γ-stimulated HaCaT cells with or without BPTSS or silymarin, a positive control for skin inflammation. To measure Th2 cytokines, primary mouse splenocytes were treated with BPTSS and performed ELISA for interleukin (IL)-4, 5, 13. Calibration curves were acquired with r2>0.9999. The contents of geniposide, liquiritin, baicalin, and glycyrrhizin in BPTSS were 5.06 ㎎/g, 7.33 ㎎/g, 27.56 ㎎/g, and 7.81 ㎎/g, respectively. BPTSS reduced TARC and RANTES production and mRNA expression in TNF-α and IFN-γ-treated HaCaT cells. BPTSS inhibited IL-4, 5, and 13 production in mouse splenocytes. Our data will be a helpful information to upgrade quality control and anti-allergic effects of BPTSS.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.207-211
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• 2000

We have studied on the determination of Ni(II) using APDC as a complexing agent in Tween80 micellar medium. The absorption spectrum of Ni(PDC)$_2$ complex in Tween80 medium was better defined and more sensitive than that in chloroform Ni(PDC)$_2$ complex was very stable at pH 7.0 and up to 100 minutes, and could be quantitatively chelated when APDC was added to over 10 times moles of Ni(II). The optimum concentration of Tween80 was 0.1%. The calibration curve of Ni(PDC)$_2$ complex with good linearity(R$^2$=0.9955) was obtained in 0.1% Tween80 medium. The detection limit and the determination limit were 0.09 ${\mu}g$/mL and 0.28 ${\mu}g$/mL, respectively. This technique was applied to the analysis of Suwon stream water samples, and about l00% of recoveries were obtained from the spiked samples. Although the formation of Ni(PDC)$_2$ complex was interfered by various metal ions, this technique could be applied to the practical determination of Ni(II).

• Applied Biological Chemistry
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• v.48 no.3
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• pp.267-272
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• 2005

trans-Cinnamaldehyde, a major component of Cinnamomum cassia, was quantitatively analyzed using the $^1H-NMR$ spectrometry. Applicability of this method was confirmed through observing the variation of chemical shift in the $^1H-NMR$ spectrum of t-cinnamaldehyde and the integration value according to various sample concentrations or running temperatures. When the $^1H-NMR$ spectrometry was run for t-cinnamaldehyde (7.1429 mg/ml) at 19, 25, 30, 40 and $50^{\circ}C$, the chemical shifts of the doublet methine signal due to an aldehyde group were observed at 9.7202, 9.7184, 9.7169, 9.7142 and 9.7124 ppm, respectively, to imply that the running temperature had no significant variation in the chemical shift of the signal. The integration values of the signal were $1.37\;(19^{\circ}C),\;1.37\;(25^{\circ}C),\;1.37\;(30^{\circ}C),\;1.37(40^{\circ}C)$ and $1.37(50^{\circ}C)$, respectively, to also indicate running temperature gave no effect on the integration value. When the sample solutions with various concentrations such as 0.4464, 0.8929, 1.7857, 3.5714, 7.1429 and 14.286 mg/ml were respectively measured for the $^1H-NMR$ at $25^{\circ}C$, the chemical shifts of the aldehyde group were observed at 9.7206, 9.7201, 9.7196, 9.7192, 9.7185 and 9.7174 ppm. Even though the signal was slightly shifted to the high field in proportion to the increase of sample concentration, the alteration was not significant enough to applicate this method. The calibration curve for integration values of the doublet methine signal due to the aldehyde group vs the sample concentration was linear and showed very high regression rate ($r^2=1.0000$). Meantime, the $^1H-NMR$ spectra (7.1429 mg/ml $CDCl_3,\;25^{\circ}C$) of t-cinnamaldehyde and t-2-methoxycinnamaldehyde, another constituent of Cinnamomum cassia, showed the chemical shifts of the aldehyde group as ${\delta}_H$ 9.7174 (9.7078, 9.7270) for the former compound and ${\delta}_H$ 9.6936 (9.6839, 9.7032) for the latter one. The difference of the chemical shift between two compounds was big enough to be distinguished using the NMR spectrometer with 0.45 Hz of resolution. The contents of cinnamaldehyde in Cinnamomum cassia, which were respectively extracted with n-hexane, $CHCl_3$, and EtOAc, were determiend as 94.2 \;mg/g (0.94%), 137.6 mg/g (1.38%) and 140.1 mg/g(1.40%) t-cinnamaldehyde in each extract, respectively, by using the above method.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.301-308
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• 2019

The antioxidant properties of Eriobotrya japonica leaf extract were investigated using DPPH and ABTS radical scavenging assay. The 80% ethanol extract of leaves ($IC_{50}$ values for DPPH and ABTS were 13.9 and $10.9{\mu}g/mL$, respectively) and young leaves ($IC_{50}$ values for DPPH and ABTS were 20.7 and $17.3{\mu}g/mL$, respectively) showed high radical scavenging activity. Additionally, the quantitative method for estimation of ellagic acid and chlorogenic acid from E. japonica leaves was optimized by HPLC/DAD. This method showed high linearity of the calibration curve with a coefficient of correlation ($R^2$) equal to 0.999. The LOD values for ellagic acid and chlorogenic acid were 2.35 and $0.73{\mu}g/mL$, respectively, whereas LOQ values were 7.13 and $2.22{\mu}g/mL$, respectively. Recovery of the two compounds was 99.7-108.0% with RSD values less than 5.31%. These results suggest that 80% ethanol extract of E. japonica leaves could serve as a potential source of natural antioxidant for us in various industrial applications.

• Analytical Science and Technology
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• v.23 no.6
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• pp.537-543
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• 2010

Dopamine (DA) is an important neurotransmitter molecule of catecholamines. Its deficiency could lead to brain disorder such as Parkinson's disease and schizophrenia. Therefore, it is necessary to establish a suitable analytical technique with sensitivity and simplicity. A competitive enzyme-linked immunosorbent assay for DA has been optimized and characterized. Assay sensitivity is controlled by two factors in competitive immunoassay. One is a nature and concentration of competitor, and the other is those of binder, antibody. Thus, optimization was performed: BSA-DA conjugate and antibody-avidin conjugate were prepared by dual heterobifunctional coupling method using SATA and SMCC. Assay condition was optimized with $6.66\;{\mu}gmL^{-1}$ of BSA-DA and $4.17{\times}10^{-10}\;M$ of antibody-avidin conjugate. A dose-response curve was constructed, and a limit of detection and a dynamic range for DA were accomplished to $2.3{\times}10^{-2}\;{\mu}g\;mL^{-1}$ and four orders of magnitude ($1.0{\times}10^{-7}\;M$ to $1.0{\times}10^{-3}\;M$), respectively. Calibration curve was constructed on dynamic range and least-squares regression of this data gave the following relationship: absorbance = -0.1098 log[DA]+0.0353 ($R^2$ = 0.9956).