• YAKHAK HOEJI
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• v.54 no.5
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• pp.377-386
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• 2010

Single-dimensional (1-D) and two-dimensional (2-D) LC methods were utilized to separate peptides from various sources followed by MS/MS analysis. Two-dimensional ultra-high performance liquid chromatography is a useful tool for proteome analysis, providing a greater peak capacity than 1-D LC. The most popular 2-D LC approach used today for proteomic research combines strong cation exchange and reversed-phase LC. We have evaluated an alternative mode for 2-D LC of peptides using 2-D RP-RP nano UPLC Q-TOF Mass Spectrometry, employing reversed-phase columns in both separation dimensions. As control experiments, we identified 129 proteins in 1-D LC and 322 proteins in 2-D LC from E. coli extract peptides. Furthermore, we applied this method to rat primary hepatocyte and a total of 170 proteins were identified from 1-D LC, and 527 proteins were identified from all 2-D LC system. The in-depth protein profiling established by this 2-D LC MS/MS from rat primary hepatocyte could be a very useful reference for future applications in regards to drug induced liver toxicity.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.142-169
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• 2020

BACKGROUND: A new analytical method has been developed to determine 261 pesticide residues in herbal medicines. METHODS AND RESULTS: The extraction of pesticides was carried out by modified method of the Korea Food Standards Codex sample extraction and determination was performed using GC-MS/MS and LC-MS/MS. During the pre-treatment process of the test method, Solid-liquid separation was changed to centrifugation. The method was validated by the precision and accuracy results. 261 pesticides spiked at three level 20, 50, 100 ug/kg in herbal medicines. The limit of quantification of method were 4-40 ug/kg for GC-MS/MS and 2-45 ug/kg for LC-MS/MS, respectively. Among the pesticides analysed by GC-MS/MS and LC-MS/MS, 244 pesticides (94% of total number) in chinese matrimony vine and 224 pesticides (86% of total number) in korean angelica root and 231 pesticides (89% of total number) in jujube and 214 (82% of total number) in cnidium showed recoveries in the range of 70-120% with RSD⪯20%. CONCLUSION: These results indicated that GC-MS/MS and LC-MS/MS analysis with the sample extraction in this study can be applied to multi-residue analysis of pesticides in herbal medicines.

• Analytical Science and Technology
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• v.20 no.5
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• pp.400-405
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• 2007

The comparative analysis of glycerin in cosmetic samples was carried out by LC/MS and $^1H$ NMR spectrometry. For the LC/MS analysis, aqueous solution was controlled in strong basic condition with sodium hydroxide, and benzoyl chloride was added to the solution for the derivatization of glycerin. The derivative was extracted using pentane and analyzed by the LC/MS. For the $^1H$ NMR analysis, sample was directly dissolved in $D_2O$ solvent without pretreatment. The quantitative analysis of glycerin was done by $^1H$ NMR ERETIC method. The analysis results of LC/MS and $^1H$ NMR showed that the calibration curves were a good linearity with $r^2=0.9991$ in the range of 0.1 to $10{\mu}g/mL$ and $r^2=1$ in the range of 25 to $500{\mu}g/mL$, respectively.

• Analytical Science and Technology
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• v.25 no.1
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• pp.83-90
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• 2012

The objective of the study was to estimate the measurement uncertainty associated with determination of creatinine (Cr) in urine samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Centrifuged urine samples (10 ${\mu}L$) were diluted with 390 ${\mu}L$ of distilled water. To 20 ${\mu}L$ aliquots of diluted urine samples, 30 ${\mu}L$ of internal standard solution (Cr-$d_3$, 5 ${\mu}g/mL$) and 10 ${\mu}L$ of acetonitrile were added and filtered. The samples (1 ${\mu}L$) were introduced into LC-MS/MS with no further pretreatment. Cr was separated on a multi-mode ODS column (Scherzo SM-C18, 75 ${\times}$ 2.0 mm I.D., 3 ${\mu}m$) and quantified by LC-MS/MS operating in MRM mode (Cr, m/z 114.0${\rightarrow}$ 86.0; Cr-$d_3$, m/z 117.0${\rightarrow}$ 89.1). The four factors that contribute uncertainty to the final result were extracted and evaluated. The principal factors of contribution to combined standard uncertainty were sample dilution, calibration curve and repeatability, while the preparation of standard solution was only a minor factor. Relative extended uncertainty of the measured concentration was 14.2% in a real urine sample.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.110-117
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• 2018

The aim of this study was to develop an analytical method for the quantification of diazepam residues in fishery products, using liquid and gas chromatography-tandem mass spectrometry (LC-MS/MS and GC-MS/MS). The sample utilized in the study was extracted from the fish sample (crucian carp) using 0.1% formic acid in acetonitrile. For the utilization of the purification process, the dispersive solid phase extraction (dSPE) was used for LC-MS/MS, dSPE and SPE was used for GC-MS/MS, respectively. To be sure, the standard calibration curves showed a good linearity as the noted correlation coefficients, $r^2$ was > 0.99. The average recoveries for accuracy ranged in 99.8~124% for the samples which were fortified at three different levels (0.001, 0.002 and 0.010 mg/kg). The correlation coefficient for the precision effect was measured at a range of 4.01~11.8%. The limit of detection (LOD) for the diazepam analysis was 0.0004 mg/kg, and the limit of the quantification (LOQ) was 0.001 mg/kg. The proposed analytical method was characterized with a high accuracy and acceptable sensitivity to meet the established Codex Alimentarius Commission (CAC/GL71-2009) guideline requirements. We therefore established the optimal analysis method for the determination of diazepam in the fishery products using LC-MS/MS and GC-MS/MS. It would be applicable to analyze the diazepam residues in fishery products in further studies on this subject.

• Journal of the Korean Society of Tobacco Science
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• v.33 no.1
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• pp.21-27
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• 2011

Amadori compounds(1-deoxy-1-amino-2-ketoses) are important precursors of color, flavor and aroma produced in foods. Amadori compounds occur naturally in tobacco. The contribution of amadori compounds to smoke quality has been (of) interest because of their roles of the Maillard reaction in the leaf chemistry. The amounts of these compound in tobacco are affected by the processes of aging, drying and storage conditions. In this study, eight compounds were chemically synthesized because amadori compounds (have not been sold commercially these days.) were not available for obtaining commercially. The aim of this study was to develop the analytical method of amadori compounds in tobacco leaf by the liquid chromatography mass spectrometry using triple quadrupole analyzer(LC-MS/MS). This method was simple, rapid, selective and sensitive, and eight amadori compounds were simultaneously and quantitatively analyzed within 20 minutes. This method showed excellent accuracy and precision. Recovery rates of amadori compounds ranged from 86% to 102%, with relative standard deviation(RSD) ranged from 2.6% to 5.9%. This method was applied to analysis of amadori compounds contents of tobacco leaves in different varieties. Furthermore, it was expected that the method could be extended to the analysis of other amadori compounds.

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.217-227
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• 2015

Objectives: The primary aim of this study was to identify bioactive compounds in Dangnyo-hwan, a Korean herbal medicine, through instrumental analysis using LC-MS/MS and ICP, and investigate its potential use in diabetes treatment. Methods: The extract of Dangnyo-hwan has 12 medicinal herbs; these were compared with 18 marker substances selected from literature survey. Results: LC-MS/MS analysis could detect 9 of the 18 bioactive compounds: citruline, catalpol, berberine, ginsenoside Rb1, ginsenoside Rg1, oleanolic acid, β-sitosterol, mangiferin, and schizandrin. While harmful heavy metals such as As, Pb, Cd, Hg, Ni, and Cu were not present in high concentrations, Zn concentration was 4.2 mg in 100 g Dangnyo-hwan. Conclusions: Instrumental analysis such as LC-MS/MS and ICP was successfully used to identify bioactive compounds in Dangnyo-hwan. Detection of 9 bioactive substances and Zn from the herb medicine is a valuable finding, and suggests that Dangnyo-hwan is a candidate medicine for diabetes. Further investigations like in vitro assay, percent GPR 119 activity, and percent human DGAT-1 inhibition are underway.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.105-111
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• 2015

Sixteen compounds of Neobalanocarpus heimii were successfully identified directly from their plant extract using a triple quadrupole LC-MS/MS system. In order to fulfil the objectives of this work, a series of stilbene oligomers of various degrees of condensation were isolated and their structure are characterized. Out of these, four are resveratrol dimers, three trimers, and nine tetramers. The isolation process was done on a fully automated semi-preparative HPLC system. Their structures were elucidated on the basis of 1D- and 2D-NMR as well as MS data. The mass fragmentation patterns of the compounds were recorded and a retrievable in-house library was built to keep the data. In order to demonstrate the potential of this approach, the polyphenolic crude extract was analysed with the LC-MS/MS system and the MS/MS spectra extracted for each chromatographic peak of interest. The fragmentation patterns were compared with those of anticipated pure compounds that were previously recorded. All compounds were successfully identified. It is therefore believed that the LC-MS/MS potential for dereplication of structurally similar compounds in a crude mixture was thus firmly established.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.59-64
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• 2015

Purpose: Lactate has two optical isomers, L-lactate and D-lactate. In human L-lactate is the most abundant enantiomer of lactate. As plasma and urinary levels of L-lactate is associated with inherited metabolic disorders in general, D-lactate have been linked to the presence of diabetes and inflammatory bowel disease. Previously developed techniques have shown several limitations to further evaluate D-lactate as a biomarker for this condition. In this paper, we describe a highly sensitive, specific and fast liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the analysis of D-, L-lactate in urine. Methods: D- and L-lactate were quantified using high performance liquid chromatography tandem mass spectrometry (LC-MS/MS) with labelled internal standard. Samples were derivatized with (+)-O,O'-diacety-L-tartaric anhydride (DATAN) and seperated on a Poroshell 120 EC-C18 column. Results: Quantitative analysis of D-, and L-lactate was achieved successfully. Calibration curves were linear (r>0.999) over $0.5-100{\mu}g/mL$. Stabilities for samples were within the 10% varation. Inter- and Intra-day assay variations were below 10%. Conclusion: The presented method proved to be suitable for the quantitation of D- and L-lactate and opens the possibility to explore the use of D-lactate as a biomarker.

• The Journal of Korean Obstetrics and Gynecology
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• v.26 no.4
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• pp.48-65
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• 2013

Objectives: We took breast milk samples and analyzed them using HPLC and LC/MS/MS, to evaluate the effects of taking Saenghwa-tang during breastfeeding on breast milk. Methods: The study participants were 20 lactating women who admitted in Korean medical postpartum care center. Breast milks were collected from paticipants who have been administrated Saenghwa-tang for more than 3 days. We used HPLC and LC/MS/MS for the determinations of amygdalin, liquiritins, 6-gingerol, decursin and decursinol angelate in Saenghwa-tang. Results: 1. Participants' $Mean{\pm}S.D$ (standard deviation) of age is $31.05{\pm}1.96$, and 15 participants had normal delivery and 5 participants had cesarean delivery. 12 participants were primipara and 8 participants were multipara. $Mean{\pm}S.D$ of lactating date is $9.4{\pm}0.94$. 2. Using HPLC, we learned LOQ level peak that matches the peak retention time of standard components of Saenghwa-tang was not detected from 20 breast milk samples. 3. Using LC/MS/MS, decursin of Angelicae Gigantis Radix was detected from HMSP 02, HMSP 04, HMSP 06, HMSP 11, and the each concentrations are 16, 2, 64, 11 ppb. Liquiritin of Glycyrrhizae Radix was not detected from HMSP 13~HMSP 18. Conclusions: Data obtained by this approach shows that this method is reliable and suitable for determining the safety of taking Saenghwa-tang during breastfeeding.