• 한국식품영양과학회지
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• 제28권6호
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• pp.1208-1211
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• 1999

Semi HPLC using a column switching technique was used to determine the trace content of vitamin B12 in various foods. Total analytical time required less than 20 mins per sample and the recovery ratio was 99.9, 99.6, 100.1 and 99.8% for 1.0, 10.0, 100.0 and 1,000 g/kg, respectively. The content of vitamin B12 in various foods obtained using column switching method showed higher levels compared to labels in dried milk(0.5 g/100g) and in grain products(0.51~34.36 g/100g). Thus, this column switching method was more sensitive, effective and precise than the microbiological analysis currently used to determine the trace compounds like a vitamin B12.

• 한국식품과학회지
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• 제37권6호
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• pp.1024-1027
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• 2005

본 연구에서는 성장기용 조제식 중에 영양강화를 위해 첨가하는 비타민 $D_3$와 $K_1$의 함량측정을 위해 lipase를 이용하여 효소 가수분해 후 유기용매로 비타민을 추출하여 동시에 분석하는 신속분석법을 위와 같이 수행하였다. 추출된 비타민을 전처리 컬럼에서 2번의 switching time을 설정하여 농축컬럼에 홉착시킨 후 gradient mode로 2가지 이동상으로 분석컬럼에서 각각의 성분을 모두 분리하여 동시에 검출하는 방법을 사용하였다. 시료로 사용된 성장기용 조제식은 표기함량보다 다소 높게 분석되었으나, 국제표준인증물질을 시료로 사용하여 본 연구의 실험방법에 의해 측정된 값은 인증된 표준값내의 결과를 보여주었다. 따라서, 비타민 $D_3$ 또는 $K_1$을 강화한 분유, 이유식 등의 분말 유제품 중에서 함량을 측정하고자 할 때 한정된 장비와 인력으로 각각의 2가지 실험방법을 수행하기가 어렵거나 시간단축이 필요한 경우, 본 연구에서 수행한 실험방법과 같이 시료전처리를 간단하고 신속하게 수행할 뿐만 아니라 역상컬럼과 column-switching HPLC에 의해 비타민 $D_3$ 또는 $K_1$을 동시에 분석함으로써 보다 효율적인 분석을 진행 할 수 있을 것으로 사료된다.

• Archives of Pharmacal Research
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• 제17권6호
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• pp.458-461
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• 1994

A new high-performance liquid chromatographic method with column switching has been onto a Bondapak phenyl/corsil $(37-50{\;}{\mu}m)$ precolumn and polar plasma components were washed with 0.06 M borate burffer. After valve switching, the concentrated drug were eluted in the back-flush mode and separated on a ${\mu}-Bondapak$ C18 column with acetonitrilke-phosphate buffer as the mobile phae. The method showed excellent precision, accuracy and speed with detection limit of $0.01{\;}{\mug}/ml^{-1}$. Total analysis time per smaple was less than 20 min and the coefficients of variation for intra and inter-assay were less than 5.635. This method has been successfully applied to plasma smaples from eats after oral administration of omeprazole.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3629-3634
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• 2013

In this study, an improved method for the quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba leaf extract was developed. The samples were extracted with a mixture of chloroform and 50 % ethanol, after which the chloroform extract was dried and reconstituted in methanol. GAs with 13:0, 15:1, and 17:1 in the extract were successfully separated within 40 min and determined with high throughput performance using an online column-switching HPLC method using an SP column C8 SG80 ($4.6{\times}150mm$, $5{\mu}m$) and a Cadenza 5CD C18 column ($4.6{\times}150mm$, $3{\mu}m$). The developed HPLC method was validated for Ginkgo biloba leaf extract. The validation parameters were specificity, linearity, precision, accuracy, and limits of detection and quantitation (LODs and LOQs, respectively). It was found that all of the calibration curves showed good linearity ($r^2$ > 0.9993) within the tested ranges. The LODs and LOQs were all lower than $0.04{\mu}g/mL$. The established method was found to be simple, rapid, and high throughput for the quantitative analysis of GAs in ten commercial Ginkgo biloba leaf extract and dietary supplements. The samples were also analyzed in LC-electrospray ionization (ESI) tandem mass spectrometry (MS/MS) - multiple-ion reaction monitoring (MRM) mode to confirm the identification results that were obtained by the column switching HPLC-DAD method. The developed method is considered to be suitable for the routine quality control and safety assurance of Ginkgo biloba leaf extract.

• Archives of Pharmacal Research
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• 제23권5호
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• pp.441-445
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• 2000

Achiral-chiral column switching HPLC assay was developed to allow the separation and quantification of the enantiomers of terbutaline in human plasma by means of fluorescence detection. Plasma samples were prepared by solid-phase extraction with sep-pak silica, followed by HPLC assay. The enantiomers of terbutaline and the internal standard were separated from the biological matrix on a silica column, and the two enantiomers were resolved and quantified on a Sumichiral OA-4900 column. The two columns were connected by a switching valve equipped with silica trap column, The trap column was used to concentrate the terbutaline in the eluent from the achiral column before back flushing onto the chiral phase. For each enantiomers, the assay was linear between 2.5-125 ng/$m\ell$ (r=0.9999) and detection limit was 1.0 ng/$m\ell$ .

• 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.281.1-281.1
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• 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)

• 한국동물위생학회지
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• 제29권3호
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• pp.339-346
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• 2006

Semi-micro-HPLC using a column-switching technique was developed for simultaneous determination of vitamin A and E contents in infant formula. Vitamin A and E were extracted by PDA - HPLC with reversed phase column using organic solvent and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with hydrolysis method and rapid extraction. Developed method has many advantages of simple and rapid sample preparation and simultaneous determination of vitamin A and E by micro-HPLC using reversed phase column.

• 분석과학
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• 제15권6호
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• pp.529-533
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• 2002

광학이성질체 분리 컬럼, 시료처리 및 농축 컬럼이 부착된 컬럼스위칭-HPLC를 이용하여 뇨시료에서 미량의 플루비프로펜 광학이성질체를 분리 정량하는 방법을 연구하였다. 분리된 각 이성질체의 고유광회전도를 구하고, d-이성질체 및 l-이성질체를 확인하였다. 이들의 검정선의 농도범위는 각각 $0.11{\sim}5.4{\mu}g/mL$이었으며, 검출한계는 d-이성질체의 경우 $0.027{\mu}g/mL$이고, l-이성질체의 경우 $0.031{\mu}g/mL$이며, 날자간 및 날자내의 정밀도의 CV값은 각각 1.84% 이하였다. 본 분석법은 플루비프로펜 약물을 복용한 살마의 뇨중에 존재하는 플루비프로펜의 분석에 적용하였다.

• Preventive Nutrition and Food Science
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• 제8권4호
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• pp.301-305
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• 2003

This study was conducted to develop an HPLC method for determining vitamin B$_{12}$ in fortified foods which has typically been determined by microbiological assays according to AOAC and Korean Food Code approved methods. Vitamin B$_{12}$ (cyanocobalamin) was determined by reversed-phase HPLC with a triple column and UV/VIS dectector (550 nm) using the column switching technique after extraction with 5 mM potassium phosphate solution by sonication without a clean-up procedure. The recovery of spiked samples and limit of detection (LOD) by HPLC were 78.6 ∼107.5 % and 2 ppb ($\mu\textrm{g}$/kg), respectively. The LOD of the microbiological assay (MBA) was much lower than that of HPLC. The concentrations of vitamin B$_{12}$ analyzed in all tested samples (n=12) confirmed compliance with declared label claims. The range of recovery ratio by the HPLC method when compared to the microbiological assay was 76.2 ∼140.0 %. There was not significant difference between the HPLC and MBA methods (p < 0.01) with r=0.9791 and linear regression y=0.9923x-0.04. The HPLC method for determining vitamin B$_{12}$ using the column-switching technique appears to be suitable for determining vitamin B$_{12}$ concentrations above 1 $\mu\textrm{g}$/100 g in fortified foods.ied foods.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.212-216
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• 1998

A coupled achiral-chiral high-performance liquid chromatographic system has been developed for the determination of the enantiomers of salmeterol, S-(+)-salmeterol and R-(-)-salmeterol in urine. THe salmeterol was separated from the interfering components in urine and quantified on the silica column, and the enantiomeric composition was determined on a Sumichiral OA-4700 chiral stationary phase. The two columns were connected by a switching valve equipped with a silica precolumn. The two columns wer connected by a switching valve equipped with a silica precolumn. The precolumn was used to concentrate the salmeterol in the eluent from the achiral column before backflushing onto the chiral phase. The coupled system was validated.