• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1158-1164
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• 2011

5-Methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT), a psychoactive tryptamine derivative, is a hallucinogenic drug of abuse. In this study, 5-OH-DIPT and its metabolites were identified and the quantitative method was developed and validated by using hydrophilic interaction chromatography-tandem mass spectrometry (HILICMS/MS). Chromatographic separation was achieved on an Atlantis HILIC silica column ($5{\mu}m$, $100{\times}2.1\;mm$). The metabolites of 5-MeO-DIPT in rat urine were characterized via Q1 scanning and product ion scanning. As a consequence, 5-MeO-IPT, 5-OH-DIPT, 6-OH-5-MeO-DIPT and their glucuronide conjugates were detected and identified as the metabolites of 5-MeO-DIPT. Subsequently, a quantitative method for 5-MeO-DIPT and its major metabolites, 5-MeO-IPT and 5-OH-DIPT, was developed in multiple reactions monitoring (MRM) mode. The calibration curves for all analytes evidenced good linearity over the concentration range of 1-1000 ng/mL with linear correlation co-efficients ($r^2$) in excess of 0.99. The intra- and inter-day accuracy and precision were 92.2-110.2% and 1.5-9.9%, respectively.

• 한국환경농학회지
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• 제29권2호
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• pp.165-175
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• 2010

A gas chromatographic (GC) method was developed to determine residues of captan, folpet, captafol, and chlorothalonil, known as broad-spectrum protective fungicides for the official purpose. All the fungicide residues were extracted with acetone containing 3% phosphoric acid from representative samples of five agricultural products which comprised rice, soybean, apple, pepper, and cabbage. The extract was diluted with saline, and dichloromethane partition was followed to recover the fungicides from the aqueous phase. Florisil column chromatography was additionally employed for final cleanup of the extracts. The analytes were then determined by gas chromatography using a DB-1 capillary column with electron capture detection. Reproducibility in quantitation was largely enhanced by minimization of adsorption or thermal degradation of analytes during GLC analysis. Mean recoveries generated from each crop sample fortified at two levels in triplicate ranged from 89.0~113.7%. Relative standard deviations (RSD) were all less than 10%, irrespective sample types and fortification levels. As no interference was found in any samples, limit of quantitation (LOQ) was estimated to be 0.008 mg/kg for the analytes except showing higher sensitivity of 0.002 mg/kg for chlorothalonil. GC/Mass spectrometric method using selected-ion monitoring technique was also provided to confirm the suspected residues. The proposed method was reproducible and sensitive enough to determine the residues of captan, folpet, captafol, and chlorothalonil in agricultural commodities for routine analysis.

• Tuberculosis and Respiratory Diseases
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• 제39권3호
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• pp.242-247
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• 1992

연구배경 : Surfactant 단백은 surfactant의 물리학적 성상의 결정 및 대사를 조절하는데 있어서 중요한 역할을 한다. 유전자 발현의 조절을 연구하기 위하여서는 cDNA의 탐지자에 의한 mRNA의 정량측정이 중요하다. 방법 : 쥐의 surfactant 단백 B의 cDNA에 대한 coding 부위를 PGem 3Z 또는 4Z에 subclone하여 SP6 RNA polymerase 효소를 이용하여 antisense와 sense을 얻었다. Sense을 이용한 filter hybridization올 시행하여 정상곡선을 얻었다. Antisense는 $^{32}P$를 표지시켜 탐지자로 이용하였다. 결과 : SP-B에 대한 sense 복사체의 정상곡선은 Y=2034.9X+159.1(X=SP-BmRNA 복사체, Y=CPM)이고, 상관계수는 1.0이었다. 결론 : 이상의 결과로 filter hybridization 방법은 mRNA을 정량측정 하는데 있어서 빠르고, 재현성이 높으며, 많은 시료를 한꺼번에 시행할 수 있는 유용한 방법이다.

• 약학회지
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• 제54권6호
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• pp.429-440
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• 2010

HS-SPME-GC/MS was studied and optimized for the determination of 17 orgarnophosphorous pesiticides (OPPs: chlorpyrifos, chlorpyrifos-methyl, demeton-s-methyl, diazinon, dimethoate, EPN, fenitrothion, fenthion, malathion, methidathion, monocrotophos, parathion, phenthoate, phosphamidon, sulfotep, terbufos, triazophos) in blood. Optimum SPME parameters were selected: choice of SPME fiber (85 ${\mu}m$ polyacrylate), pH effect (0.5 N HCl), salt effect ($Na_2SO_4$, 0.2 g; 20%), headspace incubation temperature ($80^{\circ}C$), headspace incubation time (1 min), headspace adsorption time (30 min) and GC desorption time (2 min). These parameters were optimized using HS-SPME autosampler coupled with gas chromatography-mass spectrometry (GC-MS). Method validation was carried out in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ) and recovery in blood. The assay was linear over 0.5~5.0 mg/l ($r^2$=0.955~1.000). Limit of detection (LOD) and limit of quantitation (LOQ) in blood were determined 0.03~0.3 mg/l (S/N=3) and 0.1~1.1 mg/l (S/N=10), respectively. Relative recovery with 0.5, 1 and 5 mg/l (in blood) were 90.8%, 98.5% and 94.1%, respectively. This method will be applied to the determination of the orgarnophosphorous pesticides in postmortem blood. The proposed protocol can be an attractive alternative to be used in routine toxicological analysis.

• 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.

• 한국의학물리학회지:의학물리
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• 제12권1호
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• pp.31-39
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• 2001

핵자기공명분광학(NMR Spectroscopy)을 이용해서 우리는 생물체의 조직안에 있는 각종 대사물질들을 측정할 수 있게 되었으며, 이것은 또 지금까지 알려진 여러 방법 중에서 생물체내의 신진대사 물질이나 생화학적인 변화를 비침습적(noninvasive)으로 알아낼 수 있는 유일한 방법에 속한다. 양성자 핵자기공명분광학은 최근들어 사람이나 흑은 동물뇌의 생화학적인 특성을 연구하는데 많이 사용되어오고 있다. 핵자기공명영상은 주로 물분자에 있는 양성자의 밀도와 그들의 이완현상(relaxation phenomena)을 측정하여 영상화하지만 핵자기공명분광학은 생체조직내의 신진대사에 관한 생화학적인 정보를 제공한다. 많은 경우에 있어서 핵자기공명분광학은 CT나 MRI 영상에서는 발견할 수 없는 정보를 제공함으로써 특정질병의 진단에 사용될 수 있으며, 따라서 환자들의 질병상태를 효과적으로 진단하는데 쓰여질 수 있다. 따라서 본 연구에서는 사람의 뇌에서 수소 핵자기공명분광학을 이용하여 대사물질들의 농도를 정량화하는 방법을 시도하였다. 이를 위해 펀텀을 이용하여 대사물질들 각각의 스팩트럼을 구했고, 성인 남녀 16명을 대상으로 insula gray matter 부위의 대사물질들의 농도를 측정하였다. 그리고 이 값들은 다른 연구자들에 의해 밝혀진 값들과 매우 근사한 값을 제공하였다.

• 대한핵의학회지
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• 제27권1호
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• pp.104-111
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• 1993

Trace elements are important components in the biological system, as a structural material and metabolic controller. Neutron activation analysis (NAA) with high neutron flux and high energy resolution Ge (Li) detector coupled to multichannel analyzer (MCA) has been one of the most accurate method for the determination of ultra-trace level components, and is applicable to biological material. In human body, the NAA can be used for quantitation of trace elements in various organs and tissue with endocrinological and metabolic disease and industrial metal poisoning. In this study, Triga Mark III nuclear reactor in Korea Atomic Research Institute was used for quantitation of trace eleement in human lung cancer tissues by neutron activation analysis. In the squamous cell carcinoma tissues, Br, Hg, La, Sb, Sc, Cl, Fe and I content were lower than normal lung tissues, and K, Rb and Se content were higher. In the adenocarcinoma tissues, Fe, Au, La, Sc and Zn content were lower than normal lung tissues, and Rb, Co and Se content were higher. Rb content was higher in the adenocarcinoma tissues than in the squamous cell carcinoma tissues. Fe and Na content were higher in the squamous cell carcinoma tissues than in the adenocarcinoma tissues.

• 분석과학
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• 제23권4호
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• pp.405-413
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• 2010

축산물(소의 근육 및 간)중에 잔류하는 합성 글루코코티코이드 6종 (betamethasone, dexamethasone, prednisone, prednisolone, methylprednisolone, flumethasone)에 대한 동시분석방법을 확립하였다. 효과적인 기기분석을 위해서 시료는 C18 고체상 카트리지를 사용하여 에틸아세테이트 용매를 사용하여 추출/정제하였다. C18 컬럼을 사용하여 분리한 후 음이온 전기분무 질량분석법의 multiple reaction monitoring 방법을 사용하여 정량 및 정성 분석을 수행하였다. 효과적이고 감도있는 HPLC-MS/MS 분석을 위해서 0.1% 포름산이 포함된 물과 아세토나이트릴이 이동상 용매로 사용되었다. 메트릭스와 약물의 종류에 따라서 검출한계(LOD)는 $0.2-0.1\;{\mu}g$/kg, 정량한계(LOQ)는 $0.8-3.4{\mu}g$/kg 이었으며, 회수율은 89.5-119.6%이었다. 확립된 기존의 방법들에 비해 6종의 글루코코티코이드의 동시분석 방법이 간소화되었고, 좋은 정확도, 정밀도 및 회수율을 나타내었으며, 축산 육류 중에 잔류하는 글루코코티코이드들 분석하는데 사용될 수 있을 것이다.

• Mass Spectrometry Letters
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• 제1권1호
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• pp.25-28
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• 2010

The high-throughput identification and accurate quantification of proteins are essential strategies for exploring cellular functions and processes in quantitative proteomics. Stable isotope tagging is a key technique in quantitative proteomic research, accompanied by automated tandem mass spectrometry. For the differential proteome analysis of mouse neuronal cell lines, we used a multiplexed isobaric tagging method, in which a four-plex set of amine-reactive isobaric tags are available for peptide derivatization. Using the four-plex set of isobaric tag for relative and absolute quantitation (iTRAQ) reagents, we analyzed the differential proteome in several stroke time pathways (0, 4, and 8 h) after the mouse neuronal cells have been stressed using a glutamate oxidant. In order to obtain a list of the differentially expressed proteins, we selected those proteins which had apparently changed significantly during the stress test. With 95% of the peptides showing only a small variation in quantity before and after the test, we obtained a list of eight up-regulated and four down-regulated proteins for the stroke time pathways. To validate the iTRAQ approach, we studied the use of oxidant stresses for mouse neuronal cell samples that have shown differential proteome in several stroke time pathways (0, 4, and 8 h). Results suggest that histone H1 might be the key protein in the oxidative injury caused by glutamate-induced cytotoxicity in HT22 cells.

• Bulletin of the Korean Chemical Society
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• 제25권1호
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• pp.109-114
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• 2004

A sensitive method for quantitation of glimepiride in human plasma has been established using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS). Glipizide was used as an internal standard. Glimepiride and internal standard in plasma sample was extracted using diethyl etherethyl acetate (1 : 1). A centrifuged upper layer was then evaporated and reconstituted with the mobile phase of acetonitrile-5 mM ammonium acetate (60:40, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS in the multiple reaction monitoring (MRM) mode, glimepiride and glipizide were detected without severe interference from human plasma matrix. Glimepiride produced a protonated precursor ion ([M+H]$^+$) at m/z 491 and a corresponding product ion at m/z 352. And the internal standard produced a protonated precursor ion ([M+H]]$^+$) at m/z 446 and a corresponding product ion at m/z 321. Detection of glimepiride in human plasma by the LC-ESI/MS/MS method was accurate and precise with a quantitation limit of 0.1 ng/mL. The validation, reproducibility, stability, and recovery of the method were evaluated. The method has been successfully applied to pharmacokinetic studies of glimepiride in human plasma.