• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3971-3976
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• 2012

A simple method was developed for the analysis of seven stilbene-type fluorescent whitening agents (FWAs) in paper materials by ion-pair reversed-phase high-performance liquid chromatography with fluorescence detection. These stilbene-type FWAs included two disulfonate, two tetrasulfonate, and three hexasulfonate compounds. After optimization of chromatographic conditions, the FWAs were satisfactorily separated using a reversed-phase column (RP-18) with the following isocratic mobile phase: methanol-water (60:40) containing 17.5 mM TBABr and 10 mM citrate buffer (pH = 7.0). The calibration plot was linear in the range from 5 to 500 ng/mL for two disulfo-FWAs and from 1 to 500 ng/mL for the other five FWAs. Precision levels of the calibration curve as indicated by RSD of response factors were 1.2 and 8.1%. Limits of quantitation (LOQ) ranged from 1.2 to 11 ng/mL.

• KSBB Journal
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• v.25 no.5
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• pp.459-465
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• 2010

A simple and efficient analytical method for the simultaneous determination of seven tar color additives was developed using ion pair high performance liquid chromatography. The conditions for HPLC analysis were as follows: column, ${\mu}$-Bondapak C18 (10 ${\mu}m$, 300 ${\times}$ 3.9 mm i.d.); gradient mobile phase, 0.025 mol/L ammonium acetate (containing 0.01 mol/L tetrabutylammonium bromide)-acetonitrile-methanol (65:25:10) as a mobile for fraction A and 0.025 mol/L ammonium acetate (containing 0.01 mol/L tetrabutylammonium bromide)-acetonitrilemethanol (40:50:10) as a mobile for fraction B; flow rate, 1.0 mL/ min; detection wavelength, 254/520/620 nm. We could attain to the detection limits as 0.01~0.05 ${\mu}$g/mL (254 nm) and 0.005~0.01 ${\mu}$g/mL (520 nm) for six red tar color additives, and 0.05 ${\mu}$g/mL (254 nm) and 0.002 ${\mu}$g/mL (620 nm) for Fast green FCF. This analytical method was applicable to determine the tar color additives contained in several commercial cold syrups.

• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.503-506
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. One molar CH3COO Na solution was used as an eluent. The heavier isotope of lithium was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was calculated according to the method of Glueckauf from the elution curve and isotopic assays. The single stage separation factor of lithium isotope pair fractionation was 1.021.

• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.224-230
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• 1986

Dodecyltrimethylammonium bromide (DTAB) was examined as a counter-ion in the separation of aromatic sulfonic acids on alkylmodified silica (ODS) column by reversed-phase ion-pair chromatography. The capacity factor of acids was investigated and separation was attempted. The capacity factor of samples was influenced by the several factors such as a concentration of counter-ion, concentration of methanol, kinds and concentration of electrolyte in mobile phase as well as kinds and position of functional group in samples. Some mixtures of samples were able to be separated under optimum condition.

• Archives of Pharmacal Research
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• v.19 no.5
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• pp.396-399
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• 1996

High-performance liquid chromatographic method with UV detecction was developed for the determination of theophylline and its metabolites in human urine using ${beta}$-hydroxyethyl theophylline$({beta} -HET)$ as an internal standard. For extraction of urine sample, quality control sample and xanthine-free blank urine were mixed with decylamine (ion-paring reagent) and ${beta}$-HET. After saturation with ammonium sulfate, the mixture was then extracted with organic solvent at pH values of 4.0-4.5. All separations were performed with ion-pair chromatography using decylamine as an ion-pairing reagent and 3mM sodium acetate buffered mobile phase (pH 4.0) containing 1% (v/v) acetonitrile and 0.75 mM decylamine. The detection limits of theophylline, 1, 3-DMU, 1-MU, 3-MX and 1-MX in human urine were 0.17, 0.17, 0.39, 0.19 and 0.19 ${\mu}g$/ml, based on a signal-to-noise ratios of 3.0. The mean intraday coefficients of variation (C.V.s) of each compound on nine replicates were lower than 2.0%, while mean interday C.V.s on three days were lower than 1.6%. All separations were finished within 40miutes.

• Analytical Science and Technology
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• v.15 no.3
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• pp.190-195
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• 2002

We analysed mutation of ${\beta}_2$-adrenergic receptor gene that controls bronchial asthma by denaturing high performance liquid chromatography (DHPLC) according to ion-pair reversed-phase high performance liquid chromatography (IP-RP-HPLC). We extracted genomic DNA from 50 asthma patients, amplified DNA using PCR, and analysed PCR product by DHPLC. As a result, we obtained that mutation frequency was 15 (30%) among 50 cases. Consequently DHPLC mutation detection was confirmed that the result of direct sequencing was coincide exactly.

• Analytical Science and Technology
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• v.10 no.5
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• pp.343-349
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• 1997

Analytical method using the reversed phase ion-pair chromatography (RP-IPC) for the determination of kasugamycin(5-amino-2-methyl-6-(2,3,4,5,6-pentahydroxy cyclohexyloxy)tetrahydropyran-3-yl-amino-${\alpha}$-imino acetic acid), pesticide as fungicide bactercide has been established. The retention behavior of kasugamycin in the RP-IPC was examined with respect to the effect of concentrations of organic modifiers, pH of eluent and types and concentrations of the counter ions as ion-pair reagent. This method developed by the optimum factors, can be used for the application of the quality control in the crude product and its formulation.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.365-371
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• 1985

A cationic dye, methylene blue $(MTB^+)$ was examined as a counter ion in the separation of organic and inorganic anions by ion-pair chromatography. Nonabsorbing anions could be indirectly detected by photometric detector with the assistance of MTB^+ in visible range (665nm). A mixture of anions was able to be separated with good base line resolution and high sensitivity. The capacity factors were also determined in various experimental conditions to study retention mechanism. The retention followed the ion-interaction model where the $MTB^+$ occupies a primary layer at the stationary phase while the analyte anion and other anions in the system compete for forming the secondary layer.

• Journal of the Korean Chemical Society
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• v.30 no.3
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• pp.312-319
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• 1986

Dodecyltrimethylammonium bromide (DTAB) was examined as a counter-ion in the investigation of capacity factor and separation of aromatic carboxylic acids on alkyl-modified silica (ODS) column as a stationary phase by ion-pair chromatography on reversed-phase system. The capacity factor of samples was influenced by the several factors such as a concentration of counter-ion as well as kinds and concentration of electrolyte, concentration of methanol in mobile phase and kinds and position of functional group in sample molecule. Some mixtures of samples were able to be separated under optimum condition.

• Analytical Science and Technology
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• v.8 no.2
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• pp.161-166
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• 1995

Determination of acteoside in Pedicularis resupinata var. oppositifolia has been studied using ion pair liquid chromatography. Sample was extracted with 40mL methanol for 4 hrs. The extract was cleaned up by using Sep-Pak $C_{18}$ catridge and 8mL aqueous methanol eluent(methanol 50%, water 50%, phosphate buffer pH=8.0). Its determination was performed by means of IP-HPLC with a Hamilton PRP-1 polystyrene-divinylbenzene reversed phase column($15cm{\times}4.6mm$ i. d., $5{\mu}m$) and an aqueous methanol eluent(methanol 60%, water 40% phosphate buffer pH=8.2) containing of $5.0{\times}10^{-3}M$ tetrabutylammonium bromide. The established method was applied to the sample that was collected in area of Pyung Chang gun. As a result, its content ranges showed to be 0.062~0.076%.