• Archives of Pharmacal Research
• /
• v.9 no.4
• /
• pp.211-214
• /
• 1986

A simultaneous determination method of alkaline earth metals was attempted with the conventional high performance liquid chromatographic system. Four cations, namely, magnesium, calcium, strontium and barium ion, were injected directly as aqueous solution into an eluent containing copper chloride solution and and were successfully separated and determined on a separating column (Zipax SCX, 4.6 mm i.d. ${\times}25$ cm length, Du Pont, USA) by using a variable wavelength UV detector. The linear calibration curves were obtianed in the range from $1.0{\times}10^{-4}M$ to $5.0{\times}10^{-4}M$ and the correlation coefficient of the calibration curve for each metal of magnesium and calcium in tap water. Alkaline earth metals were determined with the conventional high performance liquid chromatographic system.

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.281.1-281.1
• /
• 2003

Purpose. The purpose of this study was to develop and validate sensitive and specific analytical method for determinination of simvastatin in human plasma by the column-switching high-performance liquid chromatography (HPLC) system with UV detection. Methods. Simvastatin and internal standard were extracted into diethyl ether from plasma. (omitted)

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.6 no.2
• /
• pp.202-208
• /
• 1996

The purposes of this study are the identification and determination of metabolites in the isolated rat liver perfusate of carbon disulfide by two-dimentional thin-layer chromatography and high performance liquid chromatography for understanding the metabolism of carbon disulfide. 2-Thio-thiazolidine-4-carboxylic acid(TTCA) was synthesized by the reaction of carbon disulfide and cysteine, and confirmed by two-dimentional thin-layer chromatography, high performance liquid chromatography, UV spectroscopy, and IR spectroscopy. The absorbance of UV detector for the simultaneous determination of TTCA and thiocarbamide was 254 nm although their maximum spectra were 273 nm and 237 nm, respectively. Two kinds of the developing solvent in the two-dimentional thin-layer chromatography were 2-butanol : 80% HCOOH : $H_2O$ (7 : 2 : 1) as the first developing solvent and 2-propanol : $H_2O$ (4 : 1) as the second developing solvent. After perfusion of carbon disulfide ($8274.23{\mu}mol$), the amount of TTCA and thiocabamide of the perfusate(100 ul) were $12.02-16.4{\mu}mol$ and $5.25-8.15{\mu}g$, respectively. The mean amount of them were $14.08{\mu}mol$ and $6.41{\mu}mol$ respectively, and the former was 2.20 times greater than the latter. For conforming the mechanism of formations of TTCA and thiocarbamide in vivo, we have to clarify whether the reactions between carbon disulfide and ammonia, ammonium salts, amides, cysteine, cystine, or proteins will be formed in vitro.

• Advances in Traditional Medicine
• /
• v.6 no.1
• /
• pp.65-67
• /
• 2006

In this study, a new extraction method was developed and two kinds of flavonoids were extracted from the mature fruit of Vaccinium uliginosum L. of China. These two kinds of flavonoids were analyzed by spectral and identified by high-performance liquid chromatography (HPLC) and UV/Vis. The extract of the fruit was total acid hydrolyzed. TLC chromatography was subsequently employed to identify the hydrolysate. Two kinds of aglycone flavonoids, quercetin and myricetin, were identified. At the same time PC chromatography was used to identify the monomer sugar in the flavonoids and it was verified as glucose. HPLC, UV/Vis, and Mass spectrum analyses revealed that the flavonoids were quercetin 3-monoglucosides and myricetin 3-monoglucosides.

• KSBB Journal
• /
• v.29 no.4
• /
• pp.232-238
• /
• 2014

The simultaneous determination of creatine monohydrate (CrM), dicyandiamide and dihydrotriazine in dietary supplements using reversed-phase high performance liquid chromatography (HPLC) was developed. Chromatography was performed on a Nuclosil 100-5 SA ($4.6{\times}250mm$) column with a mobile phase of 2.3% ammonium phosphate (pH 5.5), and UV detection at 224 nm, 212 nm, and 237 nm, respectively. The performance characteristics of HPLC were determined in terms of selectivity, linearity, precision, recovery, limit of detection (LOD), and limit of quantification (LOQ). The calibration curves were linear within the concentration range of $40.0{\sim}500.0{\mu}g/mL$ for creatine, $0.1{\sim}12.8{\mu}g/mL$ for dicyandiamide, and $0.05{\sim}6.4{\mu}g/mL$ for dihydrotriazine. The detection limits of the method were 1.09, 0.01, and $0.08{\mu}g/mL$ for creatine, dicyandiamide, and dihydrotriazine, respectively. The recoveries of creatine, dicyandiamide, and dihydrotriazine were 97.2~100.9, 92.3~106.5, and 97.2~105.5%, respectively. It is expected that the chromatographic analytical method developed in this study will be usefully applicable to simultaneous determination of creatine, dicyandiamide, and dihydrotriazine contained in dietary supplements.

• Analytical Science and Technology
• /
• v.28 no.2
• /
• pp.112-116
• /
• 2015

Extraction of quaternary ammonium compounds (choline and betaine) from plant samples (spinach) using ion exchange resin (AG1, OH⁻ form) is a very simple and inexpensive approach. However, it is very hard to determine amounts of choline and betaine simultaneously using high-performance liquid chromatography-ultraviolet (HPLC-UV) detection. Unlike choline, betaine has low molar absorptivity in UV-visible (UV-Vis) region, which makes it difficult to carry out UV-Vis detection of betaine. The mixture of quaternary ammonium compounds (choline and betaine) was derivatized using 2-bromo acetophenone as a derivatizing agent. As a result, choline did not react with the derivatizing agent, whereas betaine formed a betaine derivative. This betaine derivative exhibited detectable UV absorption with baseline separation between choline and the betaine derivative. Thus, with this method, choline and betaine can be determined simultaneously by using the HPLCUV method through one-step derivatization, which is an easy, sensitive, and reliable method.

• Journal of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.46-54
• /
• 1989

The extraction method and quantitative analysis for the fat-soluble vitamins present in food stuffs and vitamin products have been investigated. The simultaneous separation and analysis of the vitamins by reverse phase high performance liquid chromatographic method was conducted using an isocratic elution with methanol : water (95 : 5) eluent on a Novapak $C_{18}$ column. The detection of vitamins was achieved by a variable wavelength UV detector. To improve the detection sensitivity detection wavelengths were set at the highest absorption bands such as 330, 265, 285, and 290nm for the respective vitamins. The analysis for the fat-soluble vitamins was finished within 40 minutes. Alkaline hydrolysis and enzymatic hydrolysis were investigated for the sample preparation; and liquid-liquid extraction and liquid-solid extraction were attempted for the extraction of vitamins. Both hydrolysis methods were turned out to be appropriate for the analysis for vitamins A, D, and E, while for the analysis of vitamin K the enzymatic hydrolysis method demonstrated better results. Diethyl ether, pentane, and n-hexane were found to give higher recovery for the liquid-liquid extraction and silica cartridge for the liquid-solid extraction.

• Bulletin of the Korean Chemical Society
• /
• v.8 no.4
• /
• pp.272-275
• /
• 1987

Two polyacetylene compounds having diyn-ene chromophore were isolated from fresh Korean ginseng roots through solvent fractionation, partition and silica gel column chromatography. The low pressure semi-preparative liquid chromatography and high performance preparative liquid chromatography were used for final separation of polyacetylenic fractions. The chemical structures of these polyacetylenes were determined to be heptadeca-1,8-dien-4,6-diyn-3,10-diol and heptadeca-1,4-dien-6,8-diyn-3,10-diol by UV, FT-IR, $^1H\;NMR,\;^{13}C\;NMR,$ mass spectra and elemental analysis.

• Analytical Science and Technology
• /
• v.15 no.3
• /
• pp.248-255
• /
• 2002

The contents of ${\alpha}$-, ${\beta}$-, ${\gamma}$-, and $\delta$-tocopherols in sesame oils were determined by high performance liquid chromatography with UV detection. ${\alpha}$-Tocopherol contents ranged from 10.28 to 19.79 mg/g oil, ${\beta}$-tocopherol contents from 8.22 to 20.10 mg/g. However, both ${\gamma}$- and $\delta$-tocopherol were less than 1.49 mg/g or not detected. ${\gamma}$-Tocopherol was not detected from both unroasted white and black sesame seed oils. Significantly higher level of tocopherol in sesame oil than other oils is an evidence of the reason why it is highly stable and prevents oxidation. The tocopherol composition for twenty sesame oils was classified by using principal component analysis.

• Analytical Science and Technology
• /
• v.25 no.6
• /
• pp.460-466
• /
• 2012

An environmentally friendly, so-called green, high performance liquid chromatography method was developed and validated for the determination of trans, trans-muconic acid (t,t-MA) in human urine as a biomarker of benzene exposure. After urinary t,t-MA was extracted and enriched using solid-phase extraction, a MF-Ph1 SG80 ($150mm{\times}2.0mm$ I.D., 5 ${\mu}m$) column with a mobile phase of 10 mM $KH_2PO_4$ containing 0.1% $H_3PO_4$ was used for isocratic separation of t,t-MA with UV detection at 259 nm. The calibration curve was constructed in the range of 0.1-5.0 mg/L with good linearity ($r^2$=0.9992). The intra-day and inter-day precision (as RSD) were 0.9-8.5% and 3.1-4.5%, respectively. The average recovery ranged from 97.5% to 101.7%. The green sample preparation and separation with no organic solvents were successfully achieved. The validated method would be suitable for the routine biological monitoring of benzene exposure in the occupational settings.