• Analytical Science and Technology
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• v.11 no.6
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• pp.429-435
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• 1998

Free and glycine conjugated bile acids were detected fluoromatrically in high-performance liquid chromatography after derivatization with dansyl cadaverine. The coupling agent, diethyl phosphorocyanidate was used to form the amide bond between dansyl cadaverine and analytes. The dansyl derivatives of 8 bile acids were separated successfully on Cosmosil ODS column by using linear gradient elution of 20% MeOH-water/$CH_3CN$. The detection limits of cholic acid was reached 10 pg(S/N=5) per $1{\mu}l$ of injected volume. This new derivatization method would be applicable to detect the changes of bile acids in biological samples.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.294-299
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• 1999

Precolumn orthophthaldehyde (OPA) labeling method of sphingoid bases, sphingosine and sphinganine, was investigated to obtain high fluorescent detectability. In order to improve the fluorescent yield, we investigated the optimal solubility of sphingoid bases for five pre-incubation solvents by incorporating the heating procedure before OPA derivatization. The pre-incubation in ethanol prominently increased the fluorescent peak height of OPA derivative for each sphingoid bases in high performance liquid chromatography. About tenfold increase of detectability was archived by pre-incubating lipid extracts pellets in ethanol at $60^{\circ}C$ for 30 min. Optimal derivatization was performed in 30 min at ambient temperature and the fluorescent intensity of OPA derivative was stable for two weeks at $4^{\circ}C$. The detection limit of sphingosine was 0.1 pmol as injected amount. This method was applied to the determination of cellular sphingosine and sphinganine in various human lung cancer cells. This OPA procedure was prospective to be useful for quantitating the amount of sphingoid bases in other cancer cells.

• Journal of Marine Bioscience and Biotechnology
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• v.15 no.2
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• pp.96-102
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• 2023

Salicornia herbacea, a noted halophyte, has been widely researched for its diverse physiological activities. The continuous exploration of its compounds is essential. This study employed gas chromatography (GC) coupled with mass spectrometry (MS) for qualitative analysis. This involved pretreatment including trimethylsilyl (TMS) derivatization of the S. herbacea extract, facilitating its GC analysis. Five compounds, including various fatty acids and β-sitosterol, were identified by direct analysis of the methanol extract of S. herbacea without pretreatment by GC-MS. Conversely, the analysis of the TMS-derivatized extract revealed 28 distinct peaks. Quantitative analysis further indicated that the predominant compounds in the S. herbacea extract were sugars and sugar derivatives, notably glucose, fructose, and glucitol. The collective concentration of these sugars and its derivatives amounted to 116.45 mg/g, representing 11.6% of the dry weight of the raw S. herbacea. Following sugars and their derivatives, fatty acids constituted the next most abundant group of compounds. However, the presence of amino acids and organic acids was relatively low.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.65-73
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• 2016

Korea Food and Drug Administration (KFDA) has officially announced 2,4-dinitrophenylhydrazine (DNPH) derivatization - high performance liquid chromatography (HPLC) methods for analysis of formaldehyde. This study was conducted to develop a convenient derivatization method for cosmetics by improving complex pre-treatment procedures included in KFDA method. To simplify pre-treatment procedures of KFDA method, reaction conditions including pH, time and temperature were optimized. This pre-treatment method does not require complicate pre-treatment steps of KFDA method such as pH adjustment of test solution with acetate buffer (pH 5.0), solvent-solvent partitioning with dichloromethane and concentrating procedure with vacuum evaporator. Formaldehyde-dinitrophenylhydrazone (formaldehyde-DNP) product produced by derivatization reaction was separated and quantified with a reversed-phase HPLC, which was slightly modified with KFDA method. The linearity test showed good results with 0.9999 of correlation coefficient ($r^2$) in the range of 2 ~ 40 ppm of standard solutions. In this method, limit of detection (LOD) and limit of quantitation (LOQ) values for formaldehyde were 0.2 ppm and 0.5 ppm, respectively. In addition, recovery test demonstrated that the method was also accurate and reproducible. Therefore, the proposed method can be applicable to rapid analysis of formaldehyde in cosmetics.

• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.9-10
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• 2001

• Archives of Pharmacal Research
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• v.20 no.5
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• pp.486-490
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• 1997

A stereospecific HPLC method has been developed for the resolution of the enantiomers of salbutamol in human urine. After solid-phase extraction and derivatization with (S)-(-)-${\alpha}$-methyl-benzyl isocyanate, the diastereomeric derivatives were resolved $(R_s=1.59)$ on $5{\mu}M$ octadecylsilan column using 47% methanol as a mobile phase with fluorescence detection. The detection limit of each enantiomer was 10 ng/ml (S/N=3).

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.131-138
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• 1986

A specific and sensitive gas chromatographic (GC) procedure with the flame photometric detector (FPD) was developed for determination of barbiturates such as barbital, allobarbital, secobarbital, phenobarbital and thiopental in plasma. In order to evaluate the performance of the FPD, the results were campared with those of the flame ionization detector (FID). After extraction of barbiturates from plasma, the barbiturates were quantitatively N, N-dimethylthiometyl (MTM)-derivatized with methylthiomethyl chloride in 1, 8-diazabicyclo [5, 4, 0] undec-7-ene catalyst. The data indicate that the FPD is about 4 times more sensitive than the FID for barbiturates, although it is less reproducible. The FPD also produced chromatogram with less back ground for extracted plasma sample. The FPD also produced chromatogram with less background for extracted plasma sample. The minimum detectable amount of MTM-thiopental on 3% OV-225 column was 4, 4fmol and that of other MTM-barbiturate was about 10.0fmol.

• Analytical Science and Technology
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• v.6 no.4
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• pp.411-415
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• 1993

A method for UV labeling of fatty acids with 2-bromoacetyltriphenylene using 18-crown-6-ether as a catalyst is described. The procedure is rapid, simple, quantitative and applicable to the HPLC analysis of fatty acids with UV detector. They have high molar absorptivity and their detection limit was about 1ng level. Nine derivatives of saturated fatty acid($C_{12}-C_{22}$) were separated on reverse-phase column(${\mu}$-Bondapak C-18) using acetonitrile-water gradient.

• YAKHAK HOEJI
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• v.59 no.1
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• pp.6-11
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• 2015

A simple HPLC-UV method was developed and validated for the quantification of human serum isepamicin using phenylisocyanate as a derivatization agent. The linear calibration curve was obtained in the concentration range of $1{\sim}100{\mu}g/ml$ and LLOQ of $1{\mu}g/ml$. This method was validated with selectivity, linearity, precision and accuracy, leading to successful application for estimating the pharmacokinetic parameters of isepamicin in Korean healthy subjects following IV infusion of 800 mg isepamicin. The mean $t_{1/2}$ of isepamicin was $1.55{\pm}0.08hr$.

• Journal of Integrative Natural Science
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• v.4 no.3
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• pp.182-186
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• 2011

Chemical modification of porous silicon surface has been investigated to have different physical surface properties. Porous silicon modified with dodecyl functionality exhibits hydrophobic feature, however the oxidation of porous silicon to modify with hydroxyl group displays hydrophilic properties. Surface characterization for both dodecyl and hydroxyl derivatized porous silicon was investigated by FT-IR spectroscopy. To determine the surface coverage, the amine functionalized surface was reduced by dithiothreitol (DTT) and the released 2-thiopyridone was quantified by UV/vis spectroscopy.