• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.601-606
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• 2007

The chromatographic behaviors of nucleotides (inosine 5'-monophosphate, uridine 5'-monophosphate, guanosine 5'-monophosphate, and thymine monophosphate disodium salts) on a C18 column were studied with different types of ionic liquids (ILs) as additives for the mobile phase in reversed-phase liquid chromatography (RPLC). Three ILs, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF4]), and 1-ethyl-3-methylimidazolium methylsulfate ([EMIm][MS]), were used. Eluents were composed of water and methanol (90/10%, vol) with the addition of 0.5-13.0 mM of ILs. The effects of the concentration of ILs on retention and separation were investigated and discussed. The results showed that the addition of ILs affects the retention and resolution of the tested compounds. Use of 13.0 mM of [BMIm][BF4] as the eluent modifier resulted in a baseline separation of nucleotides without requiring gradient elution. This study demonstrates that ILs can be potentially applied as a mobile phase modifier in RPLC.

• Preventive Nutrition and Food Science
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• 제7권1호
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• pp.12-17
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• 2002

Simultaneous determination of nine water-soluble vitamins contained in multi-nutrient tablets was carried out by reversed phase high-performance liquid chromatography (RP-HPLC) equipped with analytical $C_{18}$ column and UV (270 nm) detector. Those standard vitamins were successfully separated within 23 minutes by gradient elution with solvent A (0.5 M potassium phosphate monobasic) and solvent B (0.25 M potassium phosphate monobasic-methanol, 1:1). Calibration curves showed good linealities with correlation coefficients (> 0.92) in tested ranged respectively. The detection limits were considered to be 2.1 ng for ascorbic acids 60 ng for Vit B$_{6}$ 3 ng for p-aminobenzoic acid, 9 ng for niacinamide, 9 ng for thiamin, 5.0 ng for folic acid and 1.5 ng for riboflavin at 0.05 a.u.f.s. Solid phase extraction through Sep-Pak (C$_{18}$ ) cartridge was successfully applied for purification of water soluble vitamins in commercial multi-nutrient tablets.ts.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1433-1436
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• 2003

A new method for the simultaneous determination of heavy metal ions in cigarette material by microwave digestion and reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed. The cigarette material was digested by microwave digestion. Lead, cadmium, mercury, nickel and tin ions in the digested samples were pre-column derivatized with tetra-(2-chlorophenyl)-porphyrin ($T_2$-CPP) to form color chelates, which were then enriched by solid phase extraction with a $C_{18}$ cartridge. The chelates were separated on a Waters Xterra$^{TM}RP_{18}$ column by gradient elution with methanol (containing 0.05 mol/L pyrrolidine-aceticacid buffer salt, pH = 10.0) and acetone (containin0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0)as mobile phase at a flow rate of 0.5mL/min and analyzed with a photodiode array detector from 350-600 nm. The detection limits of lead, cadmium, mercury, nickel and tin were 4,3,3,8 and 5 ng/L, respectively, in the original samples. This method was afforded good results.

• 대한화학회지
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• 제34권1호
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• pp.69-75
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• 1990

모자나이트 광물 중에 포함된 각각 희토류 원소를 이온회합 크로마토그래피 방법으로 분리 및 정량하였다. 정량하기 전에 양이온교환수지(Dowex 5OW-X8) 칼럼으로 희토류 원소를 집단 분리하였다. 이 때 수지 칼럼에 의하여 희토류 원소가 정량적으로 회수되며, 시료 중의 공존이온으로부터 깨끗이 분리됨을 방사성 추적자 및 유도쌍 결합 분광-질량분석법(ICP-MS)으로 각각 확인 하였다. 역상 칼럼($\mu$-Bondapak $C_{18}$)에 의하여 미량(ppm)의 희토류 원소를 pH 4.6의 $\alpha$-hydroxyisobutyric acid으로 0.05M부터 0.3M까지 기울기 용출하여 각각 분리하였다. 희토류 원소와 PAR (4-(2-pyridylazo)-resorcinol monosodium salt)과의 포스터 칼럼 착색반응을 통하여 각각의 희토류 원소를 검출하였다.

• 한국환경농학회지
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• 제34권3호
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• pp.196-203
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• 2015

BACKGROUND: Purpose of this research is HPLC analysis method development of lycopene in tomato. And then, three components of carotenoid in four kinds of tomatoes (general tomato, cherry tomato, red and orange date tomato) were compared with each other. METHODS AND RESULTS: Lycopene in tomato was extracted with hexane likes other carotenoid components using 500 mg of dried powder sample. HPLC analysis conditions were column temperature ($40^{\circ}C$), detection wavelength (454 nm), flow rate (1.0 mL/min) and injection volume ($20.0{\mu}L$). Lycopene was analyzed by the gradient elution ($60{\rightarrow}100%$) of the mobile phase solvents A[water: methanol=25: 75 (v/v)] and B[ethyl acetate]. CONCLUSION: Three components of carotenoids (lutein, ${\beta}$-carotene, lycopene) were observed in tomatoes. The total carotenoid contents was the highest in red date tomato (662.0 mg/kg dry wt.) and the lowest in orange date tomato (111.3 mg/kg dry wt.). Lycopene contents in tomatoes was the highest percentage (93%) among all the carotenoids.

• Natural Product Sciences
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• 제22권2호
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• pp.77-81
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• 2016

A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of three antibacterial flavonoids, artocarpanone, artocarpin, and cycloartocarpin in ethyl acetate extracts from Artocarpus heterophyllus heartwoods. Separation was achieved using a TSK-gel ODS-80Tm column ($5{\mu}m$, $4.6{\times}150mm$) at $25^{\circ}C$ with a gradient elution system of methanol and water as follows: 0-8 min, 60:40; 8-27 min, 80:20; 27-35 min, 60:40, v/v, at a flow rate of 1 mL/min, and a quantitative UV detection at 285 nm. The method was validated by measuring the key parameters, including specificity, linearity, sensitivity, accuracy, repeatability and reproducibility. A high degree of specificity and sensitivity was achieved. The calibration curves for all three flavonoids showed good linearity with a coefficient of determinations ($R^2$) of ${\geq}0.9995$. The recoveries of the method were from 98-104%, with good reproducibility and repeatability (RSD values of less than 2%) were also achieved. Ethyl acetate was the best solvent for extraction of these three flavonoids using the heat reflux conditions for 1 h. This optimized sample preparation and HPLC method can be practically used for a routine standardization process of the extracts from the A. heterophyllus heartwoods.

• 생약학회지
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• 제46권2호
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• pp.123-132
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• 2015

In this study, we carried out quantification analysis of the six marker components, geniposidic acid, chlorogenic acid, geniposide, pinoresinol diglucoside, liriodendrin, and genipin in the 70% ethanol extracts of non-processed Eucommiae Cortex and processed Eucommiae Cortex using a high-performance liquid chromatography coupled with photodiode array detector. The six components were separated on Gemini C₁₈ column (5 μm, 4.6×250 mm) by the gradient elution with 1.0% (v/v) acetic acid in water and 1.0% (v/v) acetic acid in acetonitrile as mobile phase. The flow rate was 1.0 mL/min and the injection volume was 10 mL. The amount of geniposidic acid, chlorogenic acid, geniposide, pinoresinol diglucoside, liriodendrin, and genipin in non-processed Eucommiae Cortex were 1.31, 0.31, 0.66, 0.46, 0.46, and 0.03%, respectively, while the amount of the six compounds in non-processed Eucommiae Cortex were 0.04-0.78, 0.01-0.14%, 0.05-0.63%, 0.01-0.37%, 0.15-0.42%, and not detected, respectively. After processing treatment, the contents of three iridoids, two lingnan, and one phenylpropanoid decreased in Eucommiae Cortex.

• 한국동물위생학회지
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• 제23권2호
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• pp.137-142
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• 2000

In order to develop a good separation and simultaneous analysis of different sugar in an artificial mixed sugar solution, we analyzed 10 sugar components in an artificial mixed sugar solution composed of fructose, glucose, mannitol, sucrose, maltose, lactose, xylose, xylitol erythritol, and trehalose with using HPLC-ELSD or HPLC-RI. Separation and quantification by HPLC-ELSD was superior to those by HPLC-RI and detection sensitivity by HPLC-ELSD was higher then that by HPLC-RI as micorgram($\mu\textrm{g}$) level. 1. The units of minimal detectable limits were showed $\mu\textrm{g}$/$m\ell$ and ng/$m\ell$ by the HPLC-RI and HPLC-ELSD, respectively. 2. The condition of ELSD was drift tube temperature $82^{\circ}C$, $N_2$ gas flow rate 2.10 SLPM, and colum oven temperature $30^{\circ}C$, respectively. Isolation and recovery rates of single sugar from the multiple sugar solution was higher at the condition (time: flow rate: D.W.:ACN MeOH, min : $m\ell$/min:v:v:v) of linear gradient elution of mobile phase as 0 : 1.00 : 15 : 85 : 0.1 : 1.00 : 6 : 90 : 4, 17 : 1.00 : 10 : 70 : 20, 28 : 1.00 : 15 : 85 : 0 an 35 : 1.00 : 15 : 85 : 0, in order.

• Mass Spectrometry Letters
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• 제5권3호
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• pp.89-93
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• 2014

Lincomycin is one of the major species among the Pharmaceuticals and Personal Care Products (PPCPs) detected from the four major rivers in Korea. The structure characterization was performed of six degradation products of lincomycin formed under the irradiation of electron beam, and the degradation efficiency as a function of the various irradiation dose and sample concentration was investigated. Electron beam (10 MeV, 0.5 mA and 5 kW) experiments for the structural characterization of degradation products that are fortified with lincomycin, were performed at the dose of 10 kGy. The separation of degradation products and lincomycin was carried out using a C18 column ($2.1{\times}100$ mm, $3.5{\mu}m$), using gradient elution with 20 mM ammonium acetate and acetonitrile. The structures of six degradation products of lincomycin were proposed by interpretation of mass spectra and chromatograms by LC-MS/MS. The mass fragmentation pathways of mass spectra in tandem mass spectrometry were also proposed. Experiments were performed of the degradation efficiency as a function of the irradiation dose intensity and the initial concentration of lincomycin in an aqueous environment. In addition, increased degradation efficiency was observed with a higher dose of electron beam and lower concentration.

• Mass Spectrometry Letters
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• 제4권3호
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• pp.55-58
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• 2013

Dioscin is a biologically active steroidal saponin with anticancer and hepatoprotective effects. A rapid, selective, and sensitive liquid chromatographic method with electrospray ionization tandem mass spectrometry was developed for the quantification of dioscin in rat plasma. Dioscin was extracted from rat plasma using ethyl acetate at acidic pH. The analytes were separated on a Halo C18 column using gradient elution of acetonitrile and 0.1% formic acid and detected by tandem mass spectrometry in selected reaction monitoring mode. The standard curve was linear ($r^2$ = 0.998) over the concentration range of 1-100 ng/mL. The lower limit of quantification was 1.0 ng/mL using 50 ${\mu}L$ of plasma sample. The coefficient of variation and relative error for intra- and inter-assay at four QC levels were 1.3 to 8.0% and -5.4 to 10.0%, respectively. This method was applied successfully to the pharmacokinetic study of dioscin after oral administration of dioscin at a dose of 29.2 mg/kg in male Sprague-Dawley rats.