• Analytical Science and Technology
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• v.6 no.1
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• pp.21-27
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• 1993

Technical grade n-hexane whose purity is 54% has been purified for HPLC use. Methylcyclopentane, 2-methylpentane, and 3-methylpentane which are hardly isolated by fractional distillation were separated by the liquid-solid chromatography using molecular sieve 5A. UV and fluorescence impurities whose contents are critically regulated for HPLC solvent were removed by the adsorptive separation with alumina and silica gel. The present method also reduced the impurities of color(APHA), acidity, water, residue after evaporation, sulfur, and thiophene content, and the impurity contents were well within the specifications of HPLC solvent.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.4
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• pp.293-298
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• 2006

A study on the feasibility of using improved computer-controlled HPLC and GC systems was carried out to shorten the time needed for measuring levels of the substrates (glucose, maltose, and glycerol) and products (acetone, butanol ethanol, acetic acid, and butyric acid) produced by Clostridium saccharobutylicum DSM 13864 during direct fermentation of sago starch to solvent. The use of HPLC system with a single injection to analyse the composition of culture broth (substrates and products) during solvent fermentation was achieved by raising the column temperature to $80^{\circ}C$. Although good separation of the components in the mixture was achieved, a slight overlap was observed in the peaks for butyric acid and acetone. The shape of the peak obtained and the analysis time of 26.66 min were satisfactory at a fixed flow rate of 0.8mL/min. An improved GC system was developed, that was able to measure the products of solvent fermentation (acetone, butanol, ethanol, acetic acid, and butyric acid) within 19.28 min. Excellent resolution for each peak was achieved by adjusting the oven temperature to $65^{\circ}C$.

• Analytical Science and Technology
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• v.17 no.4
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• pp.295-301
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• 2004

In this study, static and dynamic solvent extractions are compared for more efficient extraction of polychlorinated dibenzofurans (PCDFs) from fly ash. Static solvent extraction rather than dynamic extraction showed a higher recovery of PCDFs, which was adsorbed strongly with fly ash. The effects of parameters, such as temperature, toluene-isopropyl alcohol mixture, static and dynamic time flow rate, and solvent volume on the extraction were investigated and the variations in average recoveries of PCDFs were explained. In both extractions, temperature was an effective parameter because the higher temperature gave the higher recoveries. In dynamic solvent extraction, dynamic time was more effective than flow rate and solvent volume for the extraction of PCDFs from fly ash. Multi-layer column chromatography on neutral and acidic silica gel with n-hexane was used for cleaning up the extracts. The quantification of the PCDFs extracted was performed using HPLC-UV.

• Korean Journal of Pharmacognosy
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• v.42 no.3
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• pp.240-245
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• 2011

A high-performance liquid chromatography (HPLC) method was developed for quantitative analysis of liquiritin and glycyrrhizin in Sagunja-tang (SGT, Sijunzi-tang in Chinese), a traditional Korean medicine. HPLC analysis was performed using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array (PDA) detection at 254 nm and 280 nm for quantification of the two components in SGT. 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. Calibration curves were acquired with $r^2$ values > 0.9998, and the relative standard deviations (RSDs, %) for intra- and inter-day precision were not exceed 4.0%. The recovery of each component was in the range of 91.85 - 108.62%, with a RSD less than 4.0%. The contents of the two components in SGT were 7.94 - 13.83 mg/g.

• Microbiology and Biotechnology Letters
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• v.28 no.3
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• pp.185-187
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• 2000

Instead of using binary HPLC pump which is usually used for the generation of solvent gradient for the analysis of amino acid an isocratic HPLC pump and conventional gra-dient maker were demonstrated to perform such analysis withmuch lower expenses and similar efficiency.

• Bulletin of the Korean Chemical Society
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• v.21 no.3
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• pp.351-352
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• 2000

• Herbal Formula Science
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• v.18 no.2
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• pp.251-257
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• 2010

Objectives : To develop and validate High-performance liquid chromatography-photodiode array methods for simultaneous determination of two constituents in Oryeong-san(ORS). Methods : Reverse-phase chromatography using a Gemini C18 column operating at $40^{\circ}C$, and photodiode array(PDA) detection at 280 nm, were used for quantification of the two marker components of ORS. The mobile phase using a gradient flow consisted of two solvent systems. Solvent A was $H_2O$ and solvent B was acetonitrile. Results : Calibration curves were acquired with correlation coefficient ($r^2$)>0.9999, and the relative standard deviation(RSD) values(%) for intra- and inter-day precision were not exceed 1.0%. The recovery rate of each compound was in the range of 93.01-104.16%, with an RSD less than 2.0%. The contents of two compounds in ORS were 1.10-3.72 mg/g. Conclusions : The established HPLC method will be helpful to improve quality control of ORS.

• YAKHAK HOEJI
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• v.44 no.2
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• pp.135-140
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• 2000

Determination of Aconitum alkaloids in processed Buza (Cho-0, Salted Buza, Moist-heating Buza, Limed Buza), which had been prepared from the raw tubers of Aconitum chiisanenseb(Ranunculaceae), was established using visible spectrophotometry and high-performance liquid chromatography (HPLC) method especially for Aconitine analysis. Aconitum alkloids were reacted with tetra- thiocy-anatocobalt[II] complex ion to form a stable ion pair. The reaction product was insoluble in water but freely soluble in several organic solvents. 1.2-Dichloroethane was the best extracting solvent among the examined solvents. Spectrophotometry of Aconitum alkaloids at nax. 625 was carried out. The HPLC method for aconitine was carried out using Radial PAK-CN column with gradient solvent system by solvent mixture of acetonitrile and phosphate buffer (pH 3.0) at 4$0^{\circ}C$ and 254 nm. Linear relationship was found between absorbance response and concentration of aconitine in range of 0.45 mM~0.9 mM ($r^2$=0.9949) by spectrophotometry and 0.3 mM~1.2mM($r^2$=0.9983) by HPLC method. These methods have been found to be suitable and reproducible for routine analysis of Aconitum alkaloids and its pharmaceutical preparations.

• Analytical Science and Technology
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• v.34 no.4
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• pp.153-159
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• 2021

In this study, we describe the development of a new high-performance liquid chromatography (HPLC) method for the simultaneous analysis of six bioactive compounds (including gallic acid, epicatechin 3-gallate, quercitrin, afzelin, quercetin, and kaempferol) from Orostachys japonicus. The extraction method was investigated and optimization of the extraction time (min), solvent composition (%), and solvent to material ratio were conducted. As a result, 30 min extraction with 50% methanol and 40:1 mL/g of solvent: material ratio achieved the highest extraction efficiency with a yield of 3.32 mg/g. Furthermore, the developed HPLC method was validated and the correlation coefficient (R) values were within the satisfactory range of 0.9995-0.9999 over the linearity range of 1.53-417 ㎍/mL. The limit of detection and limit of quantification for the six active components were between 0.03-0.08 ㎍/mL and 0.08-0.26 ㎍/mL, respectively. With these newly optimized and developed methods, four batches of O. japonicus were analyzed to confirm the high extraction efficiency of the method and the feasibility of an application.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.302-304
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• 1995

As the previous HPLC method (Ogasawara et al., 1983) was described for the analysis of aclacinomycin A and some of its analogue compounds but not for aclacinomycin Y, we developed novel HPLC condition by optimizing solvent system. The newly developed solvent system allowed a complete separation of aclacinomycins Y and A, as opposed to the incomplete resolution of these two compounds in conventional method. The amounts of aclacinomycins Y and A could be accurately determined when the fermentation broth of Streptomyces lavendofoliae DKRS was analyzed by the newly developed method.