• Mass Spectrometry Letters
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• v.4 no.3
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• pp.47-50
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• 2013

An ultra-fast generic LC-MS/MS method was developed for high-throughput quantification of discovery pharmacokinetic (PK) samples and its reliability was verified. The method involves a simple protein precipitation for sample preparation and the analysis by ultra-fast generic LC-MS/MS with the ballistic gradient program and selected reaction monitoring (SRM) mode. Approximately 290 new chemical entities (NCEs) (over 10,000 samples) from 5 therapeutic programs were analyzed. The calibration curves showed good linearity in the concentration range of 1, 2 or 5 to 2000 ng/mL. No significant ion suppression was observed in the elution region of all the NCEs. When approximately 300 plasma samples were continuously analyzed, the peak area of internal standard was constant and reproducible. In the repeated analysis of samples, the plasma concentrations and the area under the curve (AUC) were consistent with the results from the first analysis. These results showed that the present ultra-fast generic LC-MS/MS method is reliable in terms of selectivity, sensitivity, and reproducibility and could be useful for high-throughput quantification and other bioanalysis in drug discovery.

• Korean Journal of Pharmacognosy
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• v.49 no.1
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• pp.76-83
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• 2018

A traditional herbal formula, Gyeji-tang has been used to treat the early colds, headache, chills, and fever in Asian countries. In this study, we were performed simultaneous determination of the 14 bioactive marker compounds, gallic acid, spinosin, paeoniflorin, albiflorin, liquiritin apioside, liquiritin, 6'''-feruloylspinosin, liquilitigenin, coumarin, cinnmamic acid, benzoylpaeoniflorin, cinnamaldehyde, glycyrrhizin, and 6-gingerol in Gyeji-tang using an ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS). Analytical column was used a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$) and maintained at $45^{\circ}C$ with a flow rate of 0.3 mL/min. The mobile phase consists of 0.1% (v/v) formic acid in water and acetonitrile with gradient elution. The MS analysis was conducted using multiple reaction monitoring in the positive and negative modes by a Waters ACQUITY TQD LC-MS/MS system. The calibration curves of 14 bioactive marker compounds showed linearity with correlation coefficients ${\geq}0.9798$. The limits of detection and quantification values were in the range of 0.11-6.66 ng/mL and 0.34-19.99 ng/mL, respectively. As a result of the analysis using the established LC-MS/MS method, the amounts of tested 14 compounds in the lyophilized Gyeji-tang sample were detected up to $85.7{\mu}g/g$. These results may be useful for quality assessment of a traditional herbal formulas.

• Korean Journal of Pharmacognosy
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• v.48 no.4
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• pp.320-328
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• 2017

Yongdamsagan-tang has been used to treat the urinary disorders, acute- and chronic-urethritis, and cystitis in Korea. In this study, an ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS) method was established for simultaneous analysis of the 20 bioactive marker compounds, geniposidic acid, chlorogenic acid, geniposide, liquiritin apioside, acteoside, calceolarioside B, liquiritin, nodakenin, baicalin, liquiritigenin, wogonoside, baicalein, glycyrrhizin, wogonin, glycyrrhizin, wogonin, saikosaponin A, decursin, decursinol angelate, alisol B, alisol B acetate, and pachymic acid in traditional herbal formula, Yongdamsagan-tang. Chromatographic separations of all marker compounds were conducted using a Waters Acquity UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}m$) at $45^{\circ}C$ using a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile with gradient elution. The MS analysis was performed using a Waters ACQUITY TQD LC-MS/MS coupled with an electrospray ionization source in the positive and negative modes. The flow rate was 0.3 mL/min and injection volume was $2.0{\mu}L$. The correlation coefficient of 20 marker compounds in the test ranges was 0.9943-1.0000. The limits of detection and quantification values of the all marker components were 0.11-6.66 and 0.34-19.99 ng/mL, respectively. As a result of the analysis using the optimized LC-ESI-MS/MS method, three compounds, geniposidic acid (from Plantaginis Semen), alisol B (from Alismatis Rhizoma), and pachymic acid (from Poria Sclerotium), were not detected in this sample. While the amounts of the 17 compounds except for the geniposidic acid, alisol B, and pachymic acid were $0.04-548.13{\mu}g/g$ in Yongdamsagan-tang sample. Among these compounds, baicalin, bioactive marker compound of Scutellariae Radix, was detected at the highest amount as a $548.13{\mu}g/g$.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.37-44
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• 2008

In this study, we tried to establish analysis methods of perchlorate with ion chromatography(IC) and liquid chromatography/mass spectrometry(LC/MS) and monitored perchlorate levels in various kinds of water and soil samples. The obtained method detection limit(MDL) of IC was 1 ppb and that of LC/MS was 0.005 ppb in water sample. We monitored the ground and spring water in Busan and the average perchlorate level in ground water was 0.031 $\pm$ 0.011 ppb and that of spring water was 0.013 $\pm$ 0.014 ppb. Wastewater samples were also examined and the levels of perchlorate ranged from 0.007 to 0.380 ppb. The perchlorate levels in all water samples investigated in this study were below the EPA guideline.

• Mass Spectrometry Letters
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• v.2 no.2
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• pp.37-40
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• 2011

Saccharin is a commonly used artificial sweetener in foodstuffs. However, for its carcinogenic dispute, it has been regulated by government bodies. In this study, isotope dilution mass spectrometry (ID-MS) was introduced for the accurate quantification of saccharin. To employ ID-LC/MS, we obtained its isotope analogue, $^{13}C_1$-sodium saccharin, by customized synthesis. Samples were spiked with $^{13}C_1$-sodium saccharin and analyzed with LC/MS in negative mode. Chromatographic conditions were optimized for the adequate chromatographic retention and separation of saccharin with a $C_{18}$ column. MS was operated with electrospray ionization by the selected ion monitoring (SIM) mode of $[M-H]^-$ for saccharin (m/z 182) and $[M-Na]^-$ for its isotope analogue (m/z 183). To validate the ID-LC/MS method for accurate measurement, we prepared a batch of a candidate material by sortifying quasi-tea-drinks with saccharin and analyzed samples gravimetrically fortified in various levels of concentration. The repeatability and reproducibility of this method was tested by analyzing the reference material. Result show that ID-LC/MS is a reliable method for the quantitative analysis of saccharin.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.471-476
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• 2000

Liquid chromatography/mass spectrometry with an atmospheric pressure chemical ionization interface (LC/APCI/MS) is evaluated for the simultaneous determination of carbamate pesticides and organophosphorus pesticides in a single chromatographic analysis. APCI mass spectra of those compounds were obtrained to study their ionization characteristics. APCI provided abundant ions such as protonated molecules and characteristic fragment ions for carbamate pesticides and organophosphorus pesticides. To evaluate the feasibility of the LC/APCI/MS for a routine quantitative analysis, the linearity and repeatability of LC/APCI/MS were examined by measuring standard solution mixtures of five carbamate pesticides and four organophosphorus pesticides over the range of 1 to 100 ㎍/mL. Teh peak areas in chromatograms of characteristic ions for those compounds showed less than 3% of variation from run to run. The standard calibration curves for the nine pesticides show good linearity in the concentration range. The detection limits of the LC/APCI/MS system for those compounds range from 0.006 to 0.2 ng.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.809-816
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• 2010

Microbial biotransformations can be used to predict mammalian drug metabolism. The present investigation deals with microbial biotransformation of valdecoxib using microbial cultures. Thirty-nine bacterial, fungal, and yeast cultures were used to elucidate the biotransformation pathway of valdecoxib. A number of microorganisms metabolized valdecoxib to various levels to yield nine metabolites, which were identified by HPLC-DAD and LC-MS-MS analyses. HPLC analysis of biotransformed products indicated that a majority of the metabolites are more polar than the substrate valdecoxib. Basing on LC-MS-MS analysis, the major metabolite was identified as a hydroxymethyl metabolite of valdecoxib, whereas the remaining metabolites were produced by carboxylation, demethylation, ring hydroxylation, N-acetylation, or a combination of these reactions. The hydroxymethyl and carboxylic acid metabolites were known to be produced in metabolism by mammals. From the results, it can be concluded that microbial cultures, particularly fungi, can be used to predict mammalian drug metabolism.

• Natural Product Sciences
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• v.27 no.4
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• pp.257-263
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• 2021

Aster species (Asteraceae) are widely distributed edible and medicinal plants, known to contain various specialized metabolites including polyphenols and saponins. However, systemic analysis on the chemical profiles of these plants have rarely been made. Here we analyzed the phytochemical constituents in leaves of 6 Aster species occurring in Korea, A. ageratoides, A. altaicus var. uchiyamae, A. glehnii, A. hispidus, A. incisus, and A. yomena, by applying a LC-MS/MS-based untargeted metabolomics approach. The analysis revealed that A. ageratoides, A. hispidus, and A. yomena are relatively rich in saponins most of which are expected to be previously unknown.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2004.11a
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• pp.296-306
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• 2004

LC/MS를 이용하여 펩타이드 혹은 단백질 같은 물질을 분석하는 실험이 급격히 늘어남에 따라 LC/MS 데이터를 자동으로 처리하는 기술에 대한 요구가 커지고 있다. 이러한 LC/MS 데이터의 자동 분석 기술에 대한 연구는 현재 활발히 진행되어 왔고, 이를 직접 구현한 여러 상용 소프트웨어들이 개발되어 있는 상태이다. LC/MS 데이터는 noise 제거, background 데이터 제거, deconvolution 알고리즘을 적용한 분자량(molecular weight) 할당 등의 작업을 거쳐 분석하게 된다. 이러한 과정을 거쳐 얻어진 분자량에 대한 데이터가 올바른 값인지 검증하는 작업이 필요하다. 본 논문에서는 이러한 검증 작업과 관련하여 Peak Clustering and Fitting(이하 PC&F)에 대한 알고리즘을 제안한다. PC&F은 peak 데이터들이 지니고 있는 속성에 대한 Mahalanobis distance를 이용하여 peak 데이터를 각 retention time에 따라 clustering 분석을 하는 작업이다. 본 논문에서 제안하는 PC&F 알고리즘을 Microsoft Visual C++ 6.0 MFC 환경에서 직접 개발한 소프트웨어(PeakClusterFitLCMS)로 실험하였다. 실험결과 PC&F 작업을 통해 동일한 구성물질로부터 발생한 peak 데이터를 모아서 보다 신뢰할 수 있는 분자량을 구할 수 있었고, 구성물질에 의해 발생되지 않은 noise peak 데이터를 찾아 제거시킬 수 있음을 확인할 수 있었다.

• Journal of the Korean Chemical Society
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• v.45 no.1
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• pp.40-44
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• 2001

Benomyl, one of the known endocrine disrupting chemicals, was analyzed to understand the its fate in water. Benomyl analysis process in water sample include the following sequential steps. Hydrolysis of benomyl into carbendazim, solvent extraction, concentration, and the concentration of final carbendazim solution was determined by LC/MS (TOF). Recoveries of the spiked samples were good with the range of 80.6 to 118.6% and the MDL was 1,600 times lower than that of LC/UVD method. The use of LC/MS (TOF) successfully eliminated the positive error incurred by interferencing materials in the matrix.