• 분석과학
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• 제34권5호
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• pp.193-201
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• 2021

We have demonstrated a sensitive analytical method of measuring oleracone D in mouse plasma using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). Oleracone D and oleracone F (internal standard) in mouse plasma samples were processed using a liquid-liquid extraction method with methyl tertbutyl ether, resulting in high and reproducible extraction recovery (80.19-82.49 %). No interfering peaks around the peak elution time of oleracone D and oleracone F were observed. The standard calibration curves for oleracone D ranged from 0.5 to 100 ng/mL and were linear with r² of 0.992. The inter- and intra-day accuracy and precision and the stability fell within the acceptance criteria. The pharmacokinetics of oleracone D following intravenous and oral administration of oleracone D at doses of 5 mg/kg and 30 mg/kg, respectively, were investigated. When oleracone D was intravenously injected, it had first-order elimination kinetics with high clearance and volume of distribution values. The absolute oral bioavailability of this compound was calculated as 0.95 %, with multi-exponential kinetics. The low aqueous solubility and a high oral dose of oleracone D may explain the different elimination kinetics of oleracone D between intravenous and oral administration. Collectively, this newly developed sensitive LC-MS/MS method of oleracone D could be successfully utilized for investigating the pharmacokinetic properties of this compound and could be used in future studies for the lead optimization and biopharmaceutic investigation of oleracone D.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1254-1259
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• 2014

We investigated whether ${\beta}$-galactosidase (${\beta}$-gal)-containing Escherichia coli cells could transfer a galactose to 2-phenoxyethanol, resulting in 2-phenoxyethanol galactoside (PE-Gal). PE-Gal was confirmed by liquid chromatography-mass spectrometry. In addition, we also confirmed that a galactose molecule was covalently bonded with PE during thin-layer chromatography analysis of the ${\beta}$-gal hydrolysate of PE-Gal. The yield for PE-Gal synthesis was about 37.5% (weight basis), which was about 7-8 times greater than that of a previous report. In addition, the concentration of ${\beta}$-gal (0.96 U/ml) used in this PE-Gal synthesis was about 20 times less than that in a previous report.

• Asian-Australasian Journal of Animal Sciences
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• 제16권12호
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• pp.1799-1803
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• 2003

The possibility of lycopene affecting egg yolk pigmentation was studied with lycopene diets containing 0, 4, 8, and $12{\mu}g/g$ meal, respectively. The addition of lycopene above $4{\mu}g/g$ meal significantly improved yolk color after four days of supplementation. The transfer of lycopene into egg yolk was confirmed by thin layer chromatography, and high-performance liquid chromatography-mass spectrometry (HPLC-MS). The deposition rate of lycopene into egg yolk was approximately 2%, which was quantitatively determined using a HPLC with a UV detector. The result indicates that lycopene is a good candidate for egg yolk pigmentation and for making functional eggs.

• Journal of Microbiology
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• 제37권4호
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• pp.185-192
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• 1999

A phenanthrene-degrading bacterium was isolated from an oil-spilled intertidal sediment sample and identified as Sphingomonas sp. KH3-2. The strain degraded polycyclic aromatic compounds such naphthalene, fluorene, biphenyl, and dibenzothiophene. When strain KH3-2 was cultured for 28 days at 25C, a total of 500 ppm of phenanthrene was degrated with a concomitant production of biomass and Folin-Ciocalteau reactive aromatic intermediates. Analysis of intermediates during phenanthrene degradation using high-performance liquid chromatography and gas chromatography/mass spectrometry indicated that Sphingomonas sp. KH3-2 primarily degrades phenanthrene to 1-hydroxy-2-naphthoic acid (1H2NA) and further metabolizes 1H2NA through the degradation pathway of naphthalene.

• 분석과학
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• 제28권6호
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• pp.460-466
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• 2015

분유 내 콜레스테롤을 정량분석하기 위한 일차분석법으로 동위원소희석 질량분석법을 개발하였다. 내부표준물질로 콜레스테롤-d₄를 사용하여 분유에 첨가하였다. 분유에 지방산과 에스테르형태로 결합되어 있는 콜레스테롤을 자유 콜레스테롤로 바꾸어주기 위해 비누화과정을 수행하였다. 비누화과정은 반응온도, 반응시간, 사용한 KOH의 농도에 따라서 최적화하였으며, 그 결과로 분유시료 0.1 g에 대해 70 ℃에서 180 분 동안 8 M의 KOH 0.8 mL를 첨가하여 반응을 진행시키는 최적화조건을 확립하였다. 이와 같은 조건으로 실험을 진행하여 재현성은 0.23%, 확장불확도는 95%의 신뢰범위에서 1.9%로 추정되었다. 확립된 동위원소희석 질량분석법의 유효화를 위해 분유내에서 콜레스테롤의 인증값을 가지는 NIST SRM을 측정하였고 이 결과가 인증값과 불확도 범위내에서 일치하는 것을 확인하였다.

• 분석과학
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• 제11권5호
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• pp.321-331
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• 1998

기체크로마토그래피/질량분석법(GC/MS)을 이용하여 물시료 중에 미량으로 함유된 19종의 여러고리방향족탄화수소류에 대한 액체-액체 추출법, disk추출법 및 고체상 추출법을 이용한 시료 매트릭스로부터 분리, 추출하는 방법을 조사하였다. GC/MS의 오븐온도프로그램을 $80{\sim}310^{\circ}C$까지 단계적으로 변화시킨 결과 19종의 PAH류를 분리할 수 있었다. 액체-액체 추출법에 의한 물시료 중 PAH류의 회수율은 71.3~109.5% 범위로 나타났고, filtration에 의한 $C_{18}$ disk추출법의 회수율은 80.7~94.9% 범위로 높게 나타났다. 그러나 $C_{18}$ Sep-Pak을 사용한 고체상 추출법의 회수율은 51.8~77.9%범위이었다. 이상의 추출법에 대한 추출 회수율, 재현성 및 실험의 편리성 등 장단점을 비교한 결과, $C_{18}$ disk를 사용한 거르기법이 PAH류의 추출에 가장 적합한 방법임을 확인하였다. 각 추출법의 검출한계(S/N=5)는 액체-액체 추출법 및 고체상 추출법의 경우 0.25~6.25 ppb, disk추출법은 0.05~1.25 ppb 범위이었다.

• 한국수산과학회지
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• 제52권5호
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• pp.461-467
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• 2019

Several studies investigating the prevention and treatment of external parasites in farmed olive flounder Paralichthys olivaceus have found that the anticoccidial agent toltrazuril sulfone is an effective antiparasitic. Prior to undertaking a full-scale study, we developed analytical methods to detect the levels of toltrazuril and toltrazuril sulfone in farmed flounder samples using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS). This analysis showed that LC-MS/MS changed the mobile phase and collision energy of toltrazuril and toltrazuril sulfone. This was validated using established conditions. Sample pre-treatment for this process involved extraction with dichloromethane and purification by liquid-liquid extraction in formic acid, acetonitrile, and h-hexane, followed by determination of all compounds by LC-MS/MS. Separation was achieved within 10 min by gradient elution using a Capcell Pak C18 ($3.0{\mu}m$, $100{\times}2.0mm$) analytical column (Shiseido UG 120V) with a mixture of 0.1% (v/v) formic acid and acetonitrile. Multiple reaction monitoring was used for selective detection of toltrazuril and toltrazuril sulfone. This method yields satisfactory results for linearity, precision, and limits of quantification. Therefore, the method established in our study will serve as a basis for further research on parasite control by toltrazuril and toltrazuril sulfone.

• Mass Spectrometry Letters
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• 제10권1호
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• pp.38-42
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• 2019

Damaurone D belongs to the genus Rosa and is a traditional medicinal product used for the treatment of depression, inflammation, and infectious diseases. The purpose of this study was to develop a simple liquid chromatography-tandem mass spectrometry method for the detection of damaurone D in rat plasma and to demonstrate its application in pharmacokinetic studies. Damaurone D and berberine (internal standard) were extracted with acetonitrile using a protein precipitation method. Mass transition was monitored in multiple reaction monitoring mode at m/z $323.2{\rightarrow}267.0$ for damaurone D and m/z $336.1{\rightarrow}320.0$ for berberine in positive ion mode. Analytical validation was conducted by evaluating the specificity, linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves were linear over 2-1000 ng/mL. The intra- and inter-day precision and accuracy of quality control samples were 4.79-13.33% and 86.23-102.75%, respectively. The matrix effect and extraction recovery were 96.11-98.47% and 96.11-102.25%, respectively. In the pharmacokinetic study after intravenous administration of damaurone D at a dose of 3 mg/kg in rats, the area under the curve and clearance of damaurone D in rat plasma were $16750.26{\pm}2676.10min{\cdot}ng/mL$ and $182.44{\pm}31.36mL/min/kg$, respectively.

• Mass Spectrometry Letters
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• 제12권3호
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• pp.66-75
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• 2021

Interleukin-4 (IL-4) and IL-13 are cytokines secreted by immune cells. Cytokines induce the proliferation of macrophages or promote the differentiation of secretory cells. The initiation and progression of allergic inflammatory diseases, such as asthma, are dependent on cytokines acting through related receptor complexes. IL-4 and IL-13 are N-glycoproteins. Glycan structures in glycoproteins play important roles in protein folding, protein stability, enzymatic function, inflammation, and cancer development. Therefore, the glycan structure of IL-4 and IL-13 needs to be elucidated in detail for the development of effective therapies. We report the first attempt to characterize the site-specific N-glycosylation of recombinant IL-4 and IL-13 via liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The tandem mass spectra of intact N-glycopeptides were identified using the Integrated GlycoProteome Analyzer (I-GPA) platform, which can automatically and rapidly analyze multiple N-glycopeptides, including their glycan composition and amino acid sequences. The recombinant IL-4 and IL-13 were identified with amino acid sequence coverages of 84% and 96%, respectively. For IL-4, 52 glycoforms on one N-glycosylation site were identified and quantified. In IL-13, 232 N-glycopeptides from three N-glycosylation sites were characterized, with the site Asn52 being the most extensively glycosylated (~80%). The complex glycans were the most abundant glycan on IL-4 and IL-13 (~96% and 91%, respectively), and the biantennary glycans were the most abundant in both recombinant IL-4 and IL-13 proteins.

• 분석과학
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• 제36권1호
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• pp.22-31
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• 2023

As the use of e-liquid cigarettes is rapidly increasing worldwide, it multiplies the potential risk undisclosed to the health of non- and smokers. To reduce the hazard, each country has its own set of regulations for controlling e-liquids. In Korea, the narrow definition of tobacco makes it difficult and have been steadily occurring tax evasion exploiting the difference in natural and artificial nicotine. Therefore, it is very important to distinguish source of nicotine for their regulation. To find biochemical discriminant markers, this study established analysis methods based on high-performance liquid chromatography coupled with diode array detector (HPLC-DAD) and high-performance liquid chromatography coupled with triple Quadrupole mass spectrometry (HPLC-MS/MS) for nicotine enantiomers and tobacco alkaloids targeted using the difference in pathways of nicotine biosynthesis and chemical synthesis. The method was validated by experimenting linearity (R² > 0.999), recovery (80.99-108.41 %), accuracy (94.11-109.73 %) and precision (0.04-8.27 %). Then, the results for discrimination of the nicotine obtained from analysis of 65 commercial e-liquid products available in Korean market was evaluated. The method successfully applied to the e-liquids and one sample labelled 'synthetic nicotine' for tax exemption was found to contain a natural nicotine product. This method can be used to determine whether an e-liquid product uses natural or artificial nicotine and monitor non-taxable e-liquid products. The method is more scientific than the existing one, which relies only on field evidence.