• Archives of Pharmacal Research
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• 제22권6호
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• pp.614-618
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• 1999

A reversed-phase high-performace liquid chromatographic method was developed to determine the optical purity of metoprolol enantiomers. The enantiomers were converted to diastereomeric derivatives using (-)-menthyl chloroformate reagent. Separation of the enantiomers as diastereomers was achieved by reversed-phase HPLC within 30 min using Inertsil C8 column. This method allowed determination of 0.05% of either enantiomer in the presence of its stereoisomer and method validation showed adequate linearity over the required range. Owing to the reaction condition during the derivatization with (-)-menthyl chloroformate, the possibility of racemization had to be established. Different ratios of (S)-(-)-metoprolol and (R)-(+)-metoprolol were prepared. Enantiomeric separation of these mixtures took place on a chiralcel OD column or, after derivatization with (-)-menthyl chloroformate, on a C8 column. The results form the these two independent separation systems were compared with trace racemization and were in very good agreement. No racemization was found during the experiment.

• 분석과학
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• 제28권2호
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• pp.79-85
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• 2015

TLC (SiO₂) 상에서 3가지 유사 암페타민 류 아민 화합물과 3가지 유도체화 시약 사이의 반응으로부터 얻어진 아민유도체의 이미지 분석으로부터 암페타민 류 화합물에 대한 신속하고 경제적인 반정량적인 분석방법을 제시하기 위하여 선행 실험을 하였다. TLC상 직접적인(in situ, co-spot) 유도체화 반응의 적정화를 시도하였고 그 TLC 결과물들을 디지털카메라로 촬영하여 이미지를 얻은 후 2가지의 이미지 분석 프로그램(CP Atlas 2.0 및 ImageJ)에 적용하여 재현성(RSD; %)과 상관성(R²)을 각각 확인 및 비교하였다. 그 결과, 반응 조건에 대한 조정이 필요하였고(반응 온도 등) 각 시료별 2가지의 농도(0.5 mg/mL 및 0.01 mg/mL)에서 반응의 재현성은 0.69~5.50% 범위이었으며 반응(2 µL per spot)의 생성물과 아민의 농도에 대한 상관성은 0.1~0.005 mg/mL의 농도 구간에서 가장 높게 나타났다(R²> 0.9906). 또한, 두 가지 프로그램 모두 재현성과 직선성에 대한 유사한 결과를 나타내어 직접적인 유도체화 반응과 TLC 이미지에 대한 이들 프로그램을 사용한 분석이 아민 화합물에 대한 반정량적인 분석으로 사용될 수 있는 가능성을 보였다.

• 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.120.2-121
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• 2003

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) mode followed by two work-up methods for comparison; isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in paper samples were extracted with acetonitrile. (omitted)

• 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.235.2-236
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• 2002

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison: EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. (omitted)

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4243-4246
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• 2012

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.68.1-68.1
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• 2003

A method for determination 11 endocrine disrupting chemicals of phenols in various samples was deloped. The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) followed by two work-up methods for comparison; isobutoxycarbonyl (isoBOC) derivatization method and tert-butyldimethylsilyl (TBDMS) derivatization method. Eleven endocrine disrupting chemicals (EDCs) of phenols in biological samples were extracted with acetonitrile and then acetonitrile layer was refrigerated at -60$^{\circ}C$ for 2 hours (freezing filtration). (omitted)

• 대한수의학회지
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• 제44권1호
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• pp.23-28
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• 2004

We established a new method to analyze moxidectin using high performance liquid chromatography(HPLC) with fluorescence derivatization in order to obtain its residual profiles in biological samples. Recovery of moxidectin in tissue was 62% at 10 ppb. Average detection reproducibility in terms of coefficience variation was 4.47% at 0.32 to 10 ppb. Residual of moxidectin was studied in 44 Yorkshire-Landrace mixed bred male pigs administered subcutaneously 0, 200, or $800{\mu}g/kg$ body weight (BW) Residual profiles of moxdectin in blood, muscle, liver, kidney and fat of pigs were described. The concentration of the moxidectin in liver after administration of moxidectin was the highest among the tissues examined. Moxidectin in liver after administration of moxidectin as $200{\mu}g/kg$ BW was declined from $10.0{\pm}3.7ng/g$ at 10 day post administration to $0.5{\pm}0.3ng/g$ level at 40 day post administration. Residual levels of moxidectin in all samples were estimated to fall below the limit of quantitation (0.32 ng/ml) after 50 day after treatment of $200{\mu}g/kg$. Moxidectin showed no abnormal observations in all the clinical findings at any concentrations under these experimental conditions. In conclusion, this analysis method by HPLC after fluorescence derivatization was very effective for the detection of moxidectin in biological samples. We suggest that 50-day is safe enough for the withdrawal time of moxidectin in pigs, following the recommendation dose by the manufacturer.

• 분석과학
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• 제34권2호
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• pp.68-77
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• 2021

Cannabis is one of the most abused drugs in Korea. The main psychoactive component in cannabis, Δ9-tetrahydrocannabinol, is metabolized to 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCCOOH) and THCCOOH-glucuronide (THCCOOH-glu) in the human liver, whereby the amount of THCCOOH-glu found in urine is twice as high as that of THCCOOH. The analytical process adapted by the majority of urine drug-testing programs involves a two-step method consisting of an initial immunoassay-based screening test followed by a confirmatory test if the screening test result is positive. In this study, a qualitative gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the detection of THCCOOH in human urine, where THCCOOH-glu was converted into THCCOOH by alkaline hydrolysis. For purification of the urine extract prior to instrumental analysis, high-speed centrifugation was used to minimize interference. In addition, an injection-port derivatization method using ethyl acetate and N,O-bis(trimethylsilyl)-trifluoroacetamide containing 1 % trimethylchlorosilane was employed to reduce the time required for derivatization, and an aliquot of the final solution was injected into the GC-MS. The method was validated by measuring the selectivity, limit of detection (LOD), and repeatability. The sensitivity, specificity, precision, accuracy, Kappa, F-measure, false positive, and false negative rate were determined by comparing the GC-MS results with those obtained using the immunoassay. The LOD was determined to be 0.32 ng/mL, while the repeatability was within 9.1 % for THCCOOH. Furthermore, a comparison study was carried out, whereby the screening immunoassay exhibited a sensitivity of 86.4 % and a specificity of 100 % compared to GC-MS. The applicability of the developed method was examined by analyzing spiked urine and forensic urine samples obtained from suspected cannabis abusers (n = 221).

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.704-708
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• 2015

For the analysis of multiple-reaction intermediates for long-chain dicarboxylic acid biotransformation, simple and reproducible methods of extraction and derivatization were developed on the basis of gas chromatography with flame ionization detector (GC-FID) instead of mass spectrometry. In the derivatization step, change of the ratio of pyridine to MSTFA from 1:3 to 9:1 resulted in higher peak intensity (p = 0.021) and reproducibility (0.6%CV) when analyzing 32 g/l ricinoleic acid (RA). Extraction of RA and ω-hydroxyundec-9-enoic acid with water containing 100 mM Tween 80 showed 90.4-99.9% relative extraction efficiency and 2-7%CV compared with those with hydrophobic ethyl acetate. In conclusion, reduction of the pyridine content and change of the extraction solvent to water with Tween 80 provided compatible derivatization and extraction methods to GC-FID-based analysis of longchain carboxylic acids.

• 분석과학
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• 제16권6호
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• pp.458-465
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• 2003

수용액 시료 중 휘발성 지방산을 HS (headspace)-SPME (Solid phase microextraction)를 이용하여 간편하고 빠르게 분석하는 방법에 대하여 연구하였다. 1-Pyrenyldiazomethane (PDAM)을 이용한 화이버 내 유도체화를 통하여 휘발성 지방산의 검출감도를 향상시킬 수 있었으며, SPME 추출조건으로 pH, 염 효과 및 초음파 추출에 대하여 조사하였다. 본 연구에서 개발된 방법을 기반으로 실제 폐수 중 휘발성 지방산을 추출하여 기체크로마토그래피/질량분석기-선택이온검색법으로 정량 분석하였다.