• Analytical Science and Technology
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• v.31 no.3
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• pp.112-121
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• 2018

The hydrothermal carbonization method has received great attention because of the conversion process from biomass. The reaction produces various products in hydrochar, bio-liquid, and gas. Even though its yield cannot be ignored in amount, it is difficult to find research papers on bio-liquid generated from the hydrothermal carbonization reaction of biomass. In particular, the heterogeneity of feedstock composition may make the characterization of bio-liquid different and difficult. In this study, bio-liquid from the hydrothermal carbonization reaction of food wastes at $230^{\circ}C$ for 4 h was investigated. Among various products, fatty acid methyl esters were analyzed using two different extraction methods: liquid-liquid extraction and column chromatography. Different elutions with various solvents enabled us to categorize the various components. The eluents and fractions obtained from two different extraction methods were analyzed by gas chromatography with a mass spectrometer (GC/MS). The composition of the bio-liquid in each fraction was characterized, and seven fatty acid methyl esters were identified using the library installed in GC/MS device.

• Journal of Life Science
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• v.19 no.12
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• pp.1698-1704
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• 2009

Gemcitabine is an anticancer drug used to treat a variety of solid tumors. The drug is rapidly inactivated by cytidine deaminase in plasma and its hydrophilicity restricts the extent of quantification that is possible using reversed-phase liquid chromatography. In this paper, we report a rapid and precise method to analyze velocity and peak efficiency using ultra-performance liquid chromatography (UPLC) with a reversed-phase column. The retention periods of gemcitabine and 2'-deoxycytidine at 283 nm were 3.2 and 2.1 min, respectively. The assay provided highly linear results in the range of $0.1{\sim}20{\mu}g/ml$ ($r^2$ > 0.999). The coefficients of variation of the intra-day and inter-day assays were less than 10.0%. We observed that the estimated average concentrations of the intra-day and inter-day assays ranged from 97.3 to 113.5% to verify the accuracy. These results suggest that this new reversed-phase UPLC method is a rapid and reliable way of determining gemcitabine levels.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.6.1-6.9
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• 2024

The document is a white paper on Hydrophilic Interaction Liquid Chromatography (HILIC) analysis method development. HILIC is a type of chromatography that uses an organic/aqueous mobile phase and a polar stationary phase. In HILIC, water is a strong solvent, and unlike in Reversed Phase Liquid Chromatography (RPLC), increasing the proportion of water in the mobile phase reduces the retention time of the analyte. The paper discusses when to consider HILIC analysis methods, the advantages of HILIC, and the challenges often encountered due to the lack of understanding of HILIC mechanisms compared to RPLC. It also provides a systematic flowchart for intelligent solutions for HILIC analysis method development, which includes a three-step approach for chromatography analysis method development. The first step involves gathering as much information as possible about the analyte (e.g., pKa, log P, log D). The second step involves analyzing the sample under different pH conditions using three HILIC columns in either isocratic or gradient mode to identify the suitable column/pH combination for the analyte. The third step involves optimizing the separation by investigating other parameters such as temperature and ionic strength, and assessing the robustness of the method. The paper emphasizes that the selection of the appropriate stationary/mobile phase combination, based on the differences between the HILIC stationary phases and the mobile phase pH, can provide high selectivity in the analysis. This step-by-step approach can help users develop an efficient analysis method.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.16 no.1
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• pp.9-18
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• 2010

For screening test of the non-volatile compounds which migrate from food packaging materials into foodstuffs, the traditional high performance liquid chromatography (HPLC) systems suffer from the lack of universal detector with high sensitivity and universality and high efficiency HPLC separation column which provides complete separation of complex mixtures into all individual substances. In this work, the use possibility of online two-dimensional liquid chromatography (2D-LC) system coupled with a charged aerosol detector (CAD), a universal detector, was reviewed. 2D-LC system permits to improve peak capacity and resolving power for complex mixtures. Charged aerosol detector (CAD) offers a new feasibility for detection of any non-volatile compounds with high sensitivity and constant response factor in a calibration range. The combination of size exclusion chromatography (SEC) and normal phase HPLC (NP-HPLC) is most frequently used for the separation of the natural and synthetic polymers which are mainly used as raw materials for the manufacture of food packaging materials. However, there is no commercial software available for data acquisition and handling and therefore the quantification in 2D-LC analysis is still rare.

• Archives of Pharmacal Research
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• v.26 no.8
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• pp.606-611
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• 2003

Byakangelicin, 9-(2,3-dihydroxy-2-methylbutoxy)-4-methoxy-7H- furo[3,2-g][l]benzopyran-7-one (BKG), a component of Angelicae dahuricae Radix, is considered to be an inhibitor of aldose reductase for the treatment of diabetic cataract. An analytical method for the isolation of BKG developed by high-performance liquid chromatography has been reported. No literature on the metabolism of BKG, however, has been found. With the purpose of identifying new metabolites of BKG, BKG (100 mg/kg) was orally administered to Sprague-Dawley rats via a gavage. Using a metabolic cage, urine was collected for 24 h, and the urine samples were extracted by liquid-liquid extraction. For structural identification of new urinary metabolites of BKG, various instrumental analyses were conducted by gas-chromatography/mass spectrometry, high-performance liquid chromatography/diode array detector, liquid chromatography/mass spectroscopy with thermospray interface and $^1H$ nuclear magnetic resonance spectroscopy. Two metabolites produced from the Ο-demethylation or Ο-dealkylation of BKG were newly identified, and another new but unknown metabolite was assumed to be the hydroxylated form of BKG. These results indicate that the major metabolic products of BKG are formed by Ο-demethylation or Ο-dealkylation of BKG side chains.

• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.556-561
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• 2010

Tomato fruits(Lycoperisicon esculentum) synthesize the glycoalkaloids dehydrotomatine and ${\alpha}$-tomatine, possibly as defense against bacteria, fungi and insects. We developed a new effective method to prepare and purify dehydrotomatine and ${\alpha}$-tomatine that exists in tomato fruits using alumina column chromatography and high performance liquid chromatography (HPLC). The tomato glycoalkaloids(TGA) in tomato was extracted with 2% acetic acid, and then precipitated with ammonium hydroxide(pH=10.5). The dry precipitate substance was applied on alumina column, and then fractionated with water saturated n-butylalcohol. The TGA(Fr. No. 26~36) were collected and dried under reduced pressure. The TGA was performed on a reverse phase HPLC(Inertsil ODS-2, $5\;{\mu}m$), eluted with acetonitrile/20mM $KH_2PO_4$(24:76, v/v) at 208 nm. Two peaks were detected on HPLC, and individual peak was collected by repeating HPLC. Furthermore, to confirm the identity dehydrotomatine and ${\alpha}$-tomatine, each peak isolated was hydrolyzed with 1N HCl into sugar and aglycone tomatidine. The sugars were converted to trimethylsilyl ester derivatives. The nature and molar ratios of sugars were identified by gas-liquid chromatography(GLC) and the aglycone by high-performance liquid chromatography(HPLC). The first peak (Rt=17.5 min) eluted from HPLC was identified as dehydrotomatine, and second peak(Rt=21.0 min) was as ${\alpha}$-tomatine. This technique has been used effectively to prepare and isolate dehydrotomatine and ${\alpha}$-tomatine from tomato fruits.

• KSBB Journal
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• v.15 no.1
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• pp.76-79
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• 2000

Complex, ill-defined mixtures of natural origin are often used as nutrients in the production of biological products through microbial fermentation. Product yields are affected by variation in these natural products. Yeast extract is a typical example of these natural products. Since it is a mixture of amino acids, peptides and nucleic acids, its composition is not well characterized. In this study, we investigated the properties of thiamine hydrochloride, riboflavin and pyridoxine hydrochlride in yeast extract by using a gel filtration chromatography, ion exchange chromatography and high performance liquid chromatography. Yeast extract solution was fractionated by gel filtration chromatography and ion exchange chromatography, and then, each fraction was analyzed by using a high performance liquid chromatography.

• KSBB Journal
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• v.25 no.3
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• pp.205-214
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• 2010

Many successive liquid-liquid extractions occur enabling purification of the crude material to occur. In high performance counter-current chromatography (HPCCC), crude material is partitioned between two immiscible layers of solvent phases. The stationary phase (SP) is retained by hydrodynamic force field effect and the mobile phase (MP) is pumped through the column. Purification occurs because of the different solubility of the components in the liquid mobile and stationary phases. There are many key benefits of liquid stationary phases such as high mass and volume injection loadings, total sample recovery, and easy scale-up. Many researchers showed that predictable scale-up from simple test is feasible with knowledge of the stationary phase retention for the planned process scale run. In this review we review the recent advances in HPCCC research and also describe the key applications such as natural products and synthetics (small or large molecules).

• Journal of Applied Biological Chemistry
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• v.56 no.1
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• pp.53-57
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• 2013

In here, we investigated the quantitative analysis method of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) with liquid chromatography-mass/mass spectrometry (LC-MS/MS) or gas chromatography-MS. Two ways of clean-up process were investigated for LC-MS/MS instrumental analysis of IAA, but both a simple dilution and hydrophile-lipophile balance (HLB) solid phase extraction (SPE) were not met the optimal recovery rates for quantitative analysis. On the other hand, the clean-up method for GC-MS was finally optimized through HLB-SPE from 250-folds diluted sample and methylation with trimethylsilyl chloride in methanol for 4 h. The limit of detection for methyl ester of IAA and IBA were both 1.4 mg/L, and recovery rates showed 93-107% from the concentrated liquid fertilizer.

• Natural Product Sciences
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• v.24 no.4
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• pp.288-292
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• 2018

High-performance countercurrent chromatography (HPCCC) coupled with reversed-phase highperformance liquid chromatography (RP-HPLC) method was developed to isolate dihydrophaseic acid 3'-O-${\beta}$-D-glucopyranoside (DHPAG) from the extract of Nelumbo nucifera seeds. Enriched DHPAG sample (2.3 g) was separated by HPCCC using ethyl acetate/n-butanol/water system (6:4:10, v/v/v, normal-phase mode, flow rate: 4.0 mL/min) to give 23.1 mg of DHPAG with purity of 88.7%. Further preparative RP-HPLC experiment gave pure DHPAG (16.3 mg, purity > 98%). The current study demonstrates that utilization of CCC method maximizes the isolation efficiency compared with that of solid-based conventional column chromatography.