• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.3
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• pp.191-195
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• 2000

Quantitation of N7-methyldeoxyguanosine (N7-MedG) produced in the in vitro N-methly-N-nitrosuourea (NMU) action on thymus DNA has been achieved by enzymatic degradation, liquid chromatoraphic separaphic separation and desorption chemical ionization tandem mass spectrometry. In conjunction with the resolving power HPLC in the separation of isomers, desorprion chemical ionization tandem mass spectrometry has utilized in determining modified nucleosides at low levels using a stable-isotope labled compound as an internal reforence. The quantitative estimation of N7-methyldeoxyguanosine was previously established by an independent HPLC analysis of methylated calf thymus DNA. A sensitive and specific methodogy for the quantitation of N7-MedG at the picomole level using HPLC combined with tandem mass spectrometry without radioisotope labeling process is presented. The potential of the liquid chromatoraphic tandem mass exposure to methlation agents in vitro.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.285-291
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• 2004

A simulated moving bed (SMB) chromatography system is a powerful tool for preparative scale separation, which can be applied to the separation of chiral compound. We have de-signed our own lab-scale SMB chromatography using 5 HPLC pumps, 6 stainless steel columns and 4 multi-position valves, to separate a racemic mixture of ketoprofen in to its enantiomers. Our design has the characteristics of the low cost for assembly for the SMB chromatography and easy repair of the unit, which differs from the designs suggested by other investigators. It is possible for the flow path through each column to be independently changed by computer control, using 4 multi-position rotary valves and 5 HPLC solvent delivery pumps. In order to prove the operability of our SMB system, attempts were made to separate the (S)-ketoprofen enantiomer from a ketoprofen racemic mixture. The operating parameters of the SMB chromatography were calculated for ketoprofen separation from a batch chromatography experiment as well as by the triangle theory. With a feed concentration of 1 mg/mL, (S)-ketoprofen was obtained with a purity of 96% under the calculated operating conditions.

• Korean Journal of Pharmacognosy
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• v.33 no.2 s.129
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• pp.88-91
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• 2002

Liquid-chromatography coupled with electrospray-ion trap mass spectrometry was applied to the analysis of the eleutherosides B and E in the Eleutherococcus senticosus cortexes. The optimum ESI/MS results were obtained in the positive ion mode using extracted ion chromatogram targeting Na-adduct molecular ion of each compound. This method allowed rapid and simple gradient separation of underivatized eleutherosides B and E without pre-purification steps at very low concentration.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.998-1000
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• 2005

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.291-294
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• 2013

• Journal of Ginseng Research
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• v.35 no.1
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• pp.31-38
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• 2011

In order to distinguish the cultivation area of Panax ginseng, principal component analysis (PCA) using quantitative and qualitative data acquired from HPLC was carried out. A new HPLC method coupled with evaporative light scattering detection (HPLC-ELSD) was developed for the simultaneous quantification of ten major ginsenosides, namely $Rh_1$, $Rg_2$, $Rg_3$, $Rg_1$, Rf, Re, Rd, $Rb_2$, Rc, and $Rb_1$ in the root of P. ginseng C. A. Meyer. Simultaneous separations of these ten ginsenosides were achieved on a carbohydrate analytical column. The mobile phase consisted of acetonitrile-water-isopropanol, and acetonitrile-water-isopropanol using a gradient elution. Distinct differences in qualitative and quantitative characteristics for ginsenosides were found between the ginseng roots produced in two different Korean cultivation areas, Ganghwa and Punggi. The ginsenoside profiles obtained via HPLC analysis were subjected to PCA. PCA score plots using two principal components (PCs) showed good separation for the ginseng roots cultivated in Ganghwa and Punggi. PC1 influenced the separation, capturing 43.6% of the variance, while PC2 affected differentiation, explaining 18.0% of the variance. The highest contribution components were ginsenoside $Rg_3$ for PC1 and ginsenoside Rf for PC2. Particularly, the PCA score plot for the small ginseng roots of six-year old, each of which was light than 147 g fresh weight, showed more distinct discrimination. PC1 influenced the separation between different sample sets, capturing 51.8% of the variance, while PC2 affected differentiation, also explaining 28.0% of the variance. The highest contribution component was ginsenoside Rf for PC1 and ginsenoside $Rg_2$ for PC2. In conclusion, the HPLC-ELSD method using a carbohydrate column allowed for the simultaneous quantification of ten major ginsenosides, and PCA analysis of the ginsenoside peaks shown on the HPLC chromatogram would be a very acceptable strategy for discrimination of the cultivation area of ginseng roots.

• Archives of Pharmacal Research
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• v.16 no.2
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• pp.99-103
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• 1993

We describe here the conditions of thin layer chromatography (TLC) and high pressures liquid chromatography (HPLC) to improve the analytical method of phosphotyrosine (p-Tyr) in biological sample. TLC was performed on silica plate with the mixture of propanol and water (2.1 : 1 v/v) as a mobile phase and $R_1$ values were 0.42, 0.39 and 0.33 for phosphotyrosine, phosphothreonine and phosphoserine, respectively. HPLC was performed on $NH_2$ column with a mobile phase of potassium biphosphate solution by UV deterction at 192 nm. The optimum condition of HPLC was obtained at 0.01 M, pH 4.5 with a clear separation within 12 min. These procedures have been applied to the analysis of phosphotyrosine obtained from tyrosine-phosphorylated enolase. Both TLC and HPLC methods were suitable to analyze tyrosine-phosphorylated protein without being affected by contaminants from hydrolysates.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.165-166
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• 2002

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.18.1-18.9
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• 2014

Objectives The purpose of this study was to determine a separation method for each arsenic metabolite in urine by using a high performance liquid chromatography (HPLC)-inductively coupled plasma-mass spectrometer (ICP-MS). Methods Separation of the arsenic metabolites was conducted in urine by using a polymeric anion-exchange (Hamilton PRP X-100, $4.6mm{\times}150mm$, $5{\mu}m$) column on Agilent Technologies 1260 Infinity LC system coupled to Agilent Technologies 7700 series ICP/MS equipment using argon as the plasma gas. Results All five important arsenic metabolites in urine were separated within 16 minutes in the order of arsenobetaine, arsenite, dimethylarsinate, monomethylarsonate and arsenate with detection limits ranging from 0.15 to $0.27{\mu}g/L$ ($40{\mu}L$ injection). We used G-EQUAS No. 52, the German external quality assessment scheme and standard reference material 2669, National Institute of Standard and Technology, to validate our analyses. Conclusions The method for separation of arsenic metabolites in urine was established by using HPLC-ICP-MS. This method contributes to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies for arsenic exposure in South Korea.

• KSBB Journal
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• v.15 no.5
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• pp.537-540
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• 2000

In developing a HPLC purification process, it was hoped that a single chromatographic system would be sufficient to abtain pure paclitaxel in high yield. However, no such system was found, due in part to the complex taxoid profile of crude paclitaxel and to the rigorous nature of the product specification. A two step HPLC purification was adopted using reverse-phase separation on C(sub)18 as a first step, and normal-phase separation on silica as the final polishing step. Impurity profiles were established and maintained for paclitaxel, which identified and quantified each impurity observed in purified paclitaxel from these two steps, all impurities at or above 0.1% were identified. Results provide information for improving the quality control of paclitaxel production.