• Bulletin of the Korean Chemical Society
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• 제16권2호
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• pp.77-79
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• 1995

• Archives of Pharmacal Research
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• 제17권5호
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• pp.360-363
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• 1994

Column--swtiching technique with a reversed-phase high performance liquid chromatographic method has been developed for the routine analysis of radioiodinated insulin and its degadation products in biological fluids. The diluted biological samples were loaded onto a precolumn packed with LiChrosorb RP-8 $(25-40{\;}{\mu}m)$ using 0.1% trifuoroacetic acid (TFA) in water as a washing solvent. After valve switching, the concentrated insulins were eluted in the back-flush mode and separated by a W-Porex $C_{18}$ column with a gradient of 0.1% TFA in water and 0.1% TFA in acetonitrile as the mobile phase. The method showed good precision, accuracy and speed with the detection limit of 20 pg/ml. Total analysis time per sample was about 40 min and the coefficients of variation were less than 8, 2%.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.398.2-398.2
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• 2002

A column switching HPLC assay was developed to allow the separation and quantitation of cetirizine in human plasma by ultraviolet (UV) detection. Plasma samples were prepared by liquid-liquid extraction. After drying, the residue was reconstituted in 20 mM phosphate buffer (pH 2.8) containing 15% acetonitrile. The samples were initially injected onto a clean-up Capcell Pak MF C18 column. (50 mm $\times$ 4.6 mm I.D.), and the chromatographic region containing the peaks of interest was followed in an analytical C18 microcolumn (250 mm$\times$1.5 mm I. D.) via column switching device. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.284.2-284.2
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• 2003

Using a column-switching technique. highly sensitive and selective semi-micro high-performance liquid chromatographic (HPLC) method has been developed for the determination of baclofen in human plasma. Following precipitation of plasma sample containing baclofen with zinc sulfate-acetonitrile, samples were directly injected on to the system. (omitted)

• Journal of Pharmaceutical Investigation
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• 제30권1호
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• pp.51-54
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• 2000

A column-switching high performance liquid chromatographic method has been developed for the determination of a fluconazole in human plasma. Each plasma sample was centrifuged for 10 min at 5000 g. After an aliqout of the supernatant was taken to nylon microcentrifuge filter, these samples were centrifuged for 10 min at 5000 g. An aliqout of the supernatant was injected directly onto the HPLC column. Deionized water was run for 2 min at a flow rate of 1.0 ml/min to retain fluconazole in an extration column, while proteins and endogenous interferences were eluted to the waste. The analyte was then back-flushed onto an analytical column, $C_{18}$ reversed-phase column. The mobile phase for analytical column, 0.01 M sodium acetate (pH 5.0)-methanol (65:35, v/v), was run at a flow rate of 1.0 ml/min. The column effluent was monitored by ultraviolet detection at 261 nm. The retention time for fluconazole was 11.76 min in human plasma. The detection limit for fluconazole in human plasma was $0.2\;{\mu}g/ml$. No interference from endogenous substances was observed.

• Archives of Pharmacal Research
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• 제24권3호
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• pp.207-210
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• 2001

A fully automated high performance liquid chromatography with column-switching was developed for the simultaneous determination of KR60436, a new reversible proton pump inhibitor, and its active metabolite O-Demethyl-KR60436 from rat plasma samples. Plasma sample (50$\mu$l) was directly introduced onto a Capcell Pak MF Ph-1 column ($10{\times}4$ mm I.D.) where primary separation was occurred to remove proteins and concentrate target Substances Using acetonitrile-Potassium Phosphate (PH 7, 0.1 M) (2 : 8, v/v). The drug molecules eluted from MF Ph-1 column were focused in an intermediate column ($10{\times}2$ I.D.) by the valve switching step. The substances enriched in intermediate column were eluted and separated on a Vydac 218MR53 column ($250{\times}3.2$ I.D.) using acetonitrilepotassium phosphate (pH 7, 0.02 M) (47:53, v/v) at a flow rate of 0.5 ml/min when the valve status was switched back to A position. The method showed excellent sensitivity (detection limit of 2 ng/ml) with small volume of samples ($50{\mu}$l), good precision and accuracy, and speed (total analysis time 24 min) without any loss in chromatographic efficiency. The response was linear ($r^2{\geq}0.797$) over the concentration range of 5-500 ng/ml.

• 분석과학
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• 제7권1호
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• pp.33-39
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• 1994

환경오염수에 미량 존재하는 페놀류를 정량하기 위한 분석법의 개발을 위하여 8가지 페놀류를 대상 시료로, 고체상 추출법을 이용한 전처리 방법을 연구하였다. XAD-4와 Dowex $1{\times}8$ 수지를 연결하여 HPLC로 분석하는 온 라인 시스템을 만들어 농축과 분리의 선택성을 높이며 자동화에 중점을 두었다. 시료를 XAD-4 컬럼에 용리시켜 페놀류를 분자흡착으로 농축시킨 후 염기성 아세토니트릴을 용리시켜 탈착시키고 계속해서 Dowex $1{\times}8$ 컬럼에 음이온교환으로 페놀류만을 선택적으로 재흡착시킨다. Dowex $1{\times}8$ 컬럼에 재흡착된 페놀류를 물로 세척한 후 HCl을 포함하는 메탄올 용액으로 재탈착시킨다. 전처리 단계는 switching 밸브에 의해 온 라인으로 연결하였고 탈착된 페놀류를 HPLC에 직접 주입하여 신속하고 신뢰성 있는 정량이 가능하였다. 각 페놀류는 90% 이상의 회수율을 나타내었다. 본 분석법의 활용성을 평가하기 위해 환경오염수에서 페놀류와 공존 가능한 유기 화합물들을 첨가시켜 조제한 실험실적 오염수를 만들어 방해 효과를 조사한 결과, 페놀류만을 선택적으로 농축-분석할 수 있었다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.278.2-278.2
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• 2003

A column-switching semi-micro HPLC method with fluorescence detection was developed for the direct analysis of rebamipide in human plasma. Plasma was filtered through a 0.45 $\mu\textrm{m}$ membrane filter and 5 ${\mu}\ell$ of the filtrate was directly injected onto the pre-column. After elution of the plasma proteins to waste, the retained rebamipide and internal standard(ofloxacin) were transferred to a C18 semi-microcolumn (5$\mu\textrm{m}$, 150 ${\times}$2.0mm) where they were separated using acetonitrile-1.4％ acetic acid (40:60, v/v) as mobile phase. (omitted)

• 분석과학
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• 제28권2호
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• pp.125-131
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• 2015

사람혈장 중 베타투 수용체 작용약 테르부탈린의 정량법을 개발하고 밸리데이션을 실시하였다. 혈장시료를 Sep-pak 실리카를 이용하여 고상추출한 후 HPLC로 측정하였다. C18 칼럼을 사용하여 혈장 중의 방해물질로부터 테르부탈린 분획을 분리하여 실리카칼럼으로 보내어 테르부탈린과 내부표준물질을 분리 정량하였다. 두 칼럼은 짧은 실리카 전칼럼이 달린 절환밸부로 연결하여 사용하였다. C18 칼럼의 이동상에 녹아있는 테르부탈린의 분획은 전칼럼에서 농축되어 실리카칼럼으로 보내지고 형광 여기파장 276 nm와 들뜸파장 306 nm로 측정하였다. 이 분석법은 여섯 명의 혈장에서 특이성이 있음을 확인하였다. 혈장 중 테르부탈린 0.4-20.0 ng/mL 농도범위에서 상관계수 0.9999로 양호한 직선성을 나타내었다. 정량한계농도는 0.4 ng/mL 농도로 정밀도가 10.1% 를 나타내었다.

• 대한약학회:학술대회논문집
• /
• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
• /
• pp.219.1-219.1
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• 2002