• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.190-195
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• 2007

A new electrochemical sensor to selectively determine epinephrine was developed and its analytical characteristics has been investigated. A glassy carbon electrode was modified with Ni(II)-macrocyclic complex which has electrocatalytic effect. It was further modified with physiologically suitable and negatively charged polyuretane benzyl L-glutamate(PUBLG). The present electrode showed long term stability and it could be applied to the selective determination of epinephrine in urine sample with various coexisting compounds. Under the optimum experimental conditions the linear range was $8.0\;{\times}\;10^{-7}\;-\;2.0\;{\times}\;10^{-4}\;M$ and the limit of detection was $1.0\;{\times}\;10^{-7}\;M$. The recovery of epinephrine in urine sample diluted 5 times with buffer solution was $101.5({\pm}3.2)%$ for 6 measurements.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.384-390
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• 2000

Metabolism study of the dye, benzidine, was performed by gas chromatography-mass selective detector (GC/MSD) in the urine of rats orally administered 100 mg/kg benzidine. Urine samples were collected in metabolic cages for 0-24, 24-48, and 48-72 hrs. Ten ml of the urine was extracted with XAD-2 resin and the XAD-2 column was eluted with methanol. After evaporation, benzidine and its metabolites were extracted with diethyl ether (for non-conjugated fraction). For conjugated metabolites, $\beta$-glucu-ronidase was added to the aqueous layer that was incubated for 1 hr at 5$0^{\circ}C$ and the aqueous layer was extracted as in non-conjugated fraction. Aliquot of trimethylsilylated derivatives was applied to the GC/MSD. The mutagenicity of benzidine and its acetylated metabolites was tested by histidine/reversion assay. Five metabolites observed and confirmed either by electron impact and chemical ionization modes of the GC/MSD, or authentic compounds were monoacetyl-, diacetyl-, hydroxyacetyl-, hydroxydiacetyl-, and hydroxy-benzidine. Monoacetyl-benzidine was more potent than benzidine in histidine/reversion assay. This data indicates that monoacetylation of benzidine may be one of the metabolites produced in metabolic activation process.

• Analytical Science and Technology
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• v.21 no.2
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• pp.84-92
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• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.

• Korean Journal of Veterinary Research
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• v.38 no.4
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• pp.929-935
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• 1998

개에서 전립선액의 채취를 위한 이중발룬카테터의 효과를 알아보고자 새로이 고안한 이중발룬카테터를 이용하여 추출한 전립선액의 오염여부를 검증하였다. 총21두의 개를 이용하여 전립선액 오염여부에 대한 검증으로서 전립선액, 생검조직 및 요도 관류액중의 요크레아틴 농도측정과 배양검사를 실시하였다. 요크레아틴 농도를 측정한 결과 전립선액(0.028mg/dl)과 조직내(0.66mg/dl)에서 세척관류액(18.71mg/dl) 보다 유의성 있게(p < 0.001) 낮은 농도를 보여 뇨성분의 혼입을 최소화할 수 있는 것으로 평가되었다. 요도부 시료의 배양검사에서 양성결과를 나타낸 12마리중, 이중발룬카테터를 이용하여 전립선액을 채취한 결과 방광으로부터의 오염을 보인 1마리를 제외하고 독립적인 배양결과를 얻을 수 있었으며, 방광 및 요도로부터의 오염방지 효과는 92%를 나타냈다. 이중발룬카테터는 전립선 요도부의 카테터 장착의 용이성 및 요도로부터 오염방지 효과를 갖고 있어 손쉽게 전립선액을 추출할 수 있는 유용한 방법이라고 사료된다.

• Analytical Science and Technology
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• v.12 no.4
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• pp.265-272
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• 1999

A simultaneous profile analysis of 19 environmental estrogens, which act like estrogen and may effect the endocrine system by binding to hormone receptors or influencing cell signaling pathways, was attempted. The present method was based on the selected ion monitoring (SIM) mode of gas chromatography/mass spectrometry (GC/MS). It involves solid-liquid extraction, enzyme hydrolysis, liquid-liquid extraction and quantitative conversion into trimethylsilyl (TMS)-ether derivatives. Analytical recovery range was 47.6 ~ 99.5% and the RSD values of within-a-day and day-to-day test were 0.66 ~ 9.33%, 1.66 ~ 16.14%, respectively. The Korean reference values for the evaluation of environmental estrogen effects were established by this method.

• Proceedings of the Ginseng society Conference
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• 1984.09a
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• pp.169-183
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• 1984

인삼의 주된 사포닌으로서 Rg,과 Rb,을 흰쥐에 투여하였을 경우에 이들 물질이 흰쥐의 장기에 흡수 또는 분포되는 상태와 배설에 대하여 연구하였다. 진세노사이드 $Rg_{1}$은 경구 투여량의 약 $1.9{\%}$가 소화관의 상부에서 흡수되었으며, 투여한지 30분 후에 최고 혈중 농도에 이르렀고 조직에서는 1.5시간 걸렸다. 그러나 뇌에서는 확인되지 않았으며 뇨와 당즙에는 2 : 5의 비로 배설되었다. $Rb_{1}$을 100mg/kg 경구투여한 결과, 소화관에서는 거의 흡수가 되지 않았으며, 한편 정맥주사(5mg/kg)의 경우는 혈중 $Rb_{1}$의 농도가 지수적으로 감소하였으며, B-phase의 반감기는 14.5시간이었다. 정맥주사후 혈청과 조직에 장시간 잔존은 활성을 나탄내는 혈청단백과의 결합과 관련이 있는 것으로 사료되며 시간에 따라 뇨로 배설되나 담즙에서는 확인되지 않았다. $Rg_{1}$과 $Rb_{1}$을 경구투여한 후 TLC와 $^{13}C$-NMR을 이용하여 위와 대장에서의 분해 상태를 연구한 결과 위에서 $Rg_{1}$의 일부가 분해, 6종류의 분해 산물이 r-everse phase TLC상에서 관찰되었고 이들 분해 산물은 약산성 (0.1N HCl, $37^{\circ}C$) 조건하에서 $Rg_{1}$의 가수분해산물과 동일하였다. 한편, $Rb_{1}$ 경구투여후 위장에서 얻은 시료중에서 미확인 분해산물이 관찰되었으며, 이 분해산물은 약산성 조건하에서 $Rb_{1}$의 가수분해산물과는 상이하다는 사실을 확인하였다. 대장에서, $Rg_{1}$은 미생물 tetracycline-susceptible bacteria와 tetracycline-resist bacteria에 의해 $Rb_{1}$과 $F_{1}$으로 분해되었으며, $Rb_{1}$은 장내의 효소와 tetracycline-resistantant bacteria에 의해 Rd와 2 종류의 미확인 물질로 분해되었다.

• YAKHAK HOEJI
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• v.57 no.6
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• pp.420-425
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• 2013

Phentermine (PT) and phenmetrazine (PM) have been widely used as anti-obesity drugs. These drugs should be used with caution due to its close relation to amphetamine in its structure and toxicity. PT and PM, amphetamine-type anorectics, have recently been considered as alternatives for methamphetamine abuse in Korea. In addition, the misuse and abuse of PT and PM obtained by illegal sources such as the internet become a serious social problem. In the present study, a simultaneous detection and quantification method for determining PT and PM in human urine was developed and validated according to the international guidelines. The urine samples were screened using a fluorescence polarization immunooassay and analyzed by gas chromatography mass spectrometry (GC-MS) after extraction using automatic solid phase extraction (SPE) with a mixed-mode cation exchange cartridge and derivatization with pentafluoropropionic anhydride (PFPA). The validation results for selectivity, linearity, limits of detection (LOD) and quantification (LOQ), intra- and inter-assay precision and accuracy and recovery were satisfactory. The validated method was successfully applied to authentic urine samples collected from 38 drug abuse suspects. PT and/or PM were identified with or without methamphetamine in urine samples. Abuse of PT and PM have increased continuously in Korea, therefore, closer supervision of the inappropriate use of anoretics is necessary.

• Analytical Science and Technology
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• v.12 no.4
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• pp.326-331
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• 1999

The metabolites of 1,2,4-trimethylbenzene (TMB) were synthesized and determined by capillary electrophoresis (CE). The optimum conditions of CE for the separation and determination of 3,4-, 2,4-, 2,5-dimethylbenzoic acid and 3,4-, 2,4-, 2,5-dimethylhippuric acid from the rat urine were as following: the fused silica capillary($75{\mu}m$ i.d. ${\times}$ 36 cm length, 29 cm to detector) was used and kept at $15^{\circ}C$. The applied voltage was 10㎸ and compounds were detected at UV 210 mnm and 254 nm. The running electrolyte was 0.1 M phosphate buffer (pH 7) containing 15 mM of ${\beta}-CD$ and 3% of 2-propanol. The relative amount of the metabolite of 1,2,4-TMB in the rat urine was 56.7% of 3,4-isomer, 30.5% of 2,4-isomer and 12.8% of 2,5-isomer. This method can be applied to the analysis of TMB-metabolites in human urine.

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.303-311
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• 2002

Isolation and identification of causative microorganisms and susceptibility testing are important in selecting appropriate antimicrobial agent. The purpose of this study was to determine the antimicrobial susceptibility patterns and identification of bacteria for the selection of a therapeutic antibiotic agent for treatment. Specimens were cultured aerobically from dog patients brought to the veterinary medical teaching hospital of Seoul National University between July 1999 and September 2000. A total of 157 isolates were from skin(63), urine(45), ear canal(31) and conjunctiva(18). The result is that the most common organisms isolated from dog patients were S. intermedius was the most common isolates from the skin, ear canal, and conjunctiva. E. coli was the most common isolated from urine. Most of gram-positive isolates were resistant to ampicillin(80.6%), erythromycin(68.8%), penicillin(86.2%), tetracycline(89.2%). Otherwise most of gam-negative isolates were resistant to ampicillin(73.4%), trimethoprim-sulfa(53.3%). E. coli was resistant to ciprofloxacin(61.5%), piperacillin (69.2%). Antimicrobial susceptibility pattern by the sampling site was not remarkably different except 5. aureus isolated from urine.

• Analytical Science and Technology
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• v.19 no.5
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• pp.433-440
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• 2006

A HPLC/UV method was developed and validated for the rapid and simultaneous determination of urinary metabolites of organic solvents, mandelic acid, hippuric acid, phenylglyoxylic acid, ortho-, meta- and para-methylhippuric acid, using a monolithic column. The mobile phase was composed of tetrabutylammonium bromide as ion-pairing reagent with a flow rate of 2.4 mL/min. The total run time was less than 2.5 min for all six analytes. Good linearities were obtained for all the metabolites with correlation coefficients above 0.9993. Intra-day precision, accuracy and inter-day precision was 0.01~7.32%, 83.9~116.3% and 0.01~7.16%, respectively. The method was validated and confirmed by quantification of the quality assurance samples of Industrial Safety and Health Research Institute, Korea Occupational Safety and Health Agency.