• Mass Spectrometry Letters
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• v.5 no.4
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• pp.104-109
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• 2014

Nonmedical use of prescription stimulants such as methylphenidate (MPH) and amphetamine (AP) by normal persons has been increased to improve cognitive functions. Due to high potential for their abuse, reliable analytical methods were required to detect these prescription stimulants in biological samples. A direct injection liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and implemented for simultaneous determination of MPH, AP and their metabolites ritalinic acid (RA) and 4-hydroxyamphetamine (HAP) in human urine. Urine sample was centrifuged and the upper layer ($100{\mu}L$) was mixed with $800{\mu}L$ of distilled water and $100{\mu}L$ of internal standards ($0.2{\mu}g/mL$ in methanol). The mixture was then directly injected into the LC-MS/MS system. The mobile phase was composed of 0.2% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Capcell Pak MG-II C18 ($150mm{\times}2.0mm$ i.d., $5{\mu}m$, Shiseido) column and all analytes were eluted within 5 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve and the assay was linear from 20 to 1500 ng/mL (HAP), 40-3000 ng/mL (AP and RA) and 2-150 ng/mL (MPH). The intra- and inter-day precisions were within 16.4%. The intra- and inter-day accuracies ranged from -15.6% to 10.8%. The limits of detection for all the analytes were less than 4.7 ng/mL. The suitability of the method was examined by analyzing urine samples from drug abusers.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.87-91
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• 2005

Although 2D-PAGE has been widely used as the primary method for protein separation, difficulties in displaying proteins with an extreme values of isoelectric paint (pI), molecular size and hydrophobicity limit the technique. In addition, time consuming steps involving protein transfer and extraction from the gel-pieces can result in sample loss. Here, we describe a novel protein separation technique with capillary size-exclusion chromatography (CSEC) for rapid protein identification from human plasma. The method includes protein fractionation along with molecular size followed by in-solution tryptic digestion and peptide analysis through reversed phase liquid chromatography (RPLC) coupled to nanoflow electrospray-tandem mass spectrometry (ESI-MS/MS). Tryptic peptides are applied an a $100\;{\mu}m\;i.d.{\times}10mm$ length pre-column and then separated on a $75\;{\mu}m{\times}200mm$ analytical column at -100 nL/min flaw rate. Proteins were identified over the wide ranges of pI (3.7-12.3) when this technique was applied to the analysis of $1-2\;{\mu}L$ of human plasma. This gel-free system provides fast fractionation and may be considered a complementary technique to SDS-PAGE in proteomics.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1149-1154
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• 2010

Liquid chromatography/mass spectrometry using isotope dilution method has been established as a primary method for the measurement of cortisol in human serum. Verification of this method was accomplished by the participation in Consultative Committee for Amount of Substance-Metrology in Chemistry (CCQM) pilot study. Two levels of cortisol certified reference materials were prepared and certified by the established method. They were used as sample materials for the proficiency testing. The expanded uncertainty in the measurement of cortisol in human serum was approximately 1.2% at 95% confidence level. The results of the proficiency testing showed a good precision among the participants, but some bias to the certified values. This means that commercial field laboratories should keep traceability chain to SI unit through available reference measurement procedures and/or available reference materials.

• Natural Product Sciences
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• v.23 no.2
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• pp.84-91
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• 2017

This study proposes a sensitive and selective liquid chromatography-electrospray ionization tandem mass spectrometry method of efficiently assessing the quality of a traditional herbal medicine called Yeonggyechulgam-tang (YGCGT). The following compounds 1 - 11, namely, liquiritin apioside (1), liquiritin (2), liquiritigene (3), coumarin (4), cinnamic acid (5), cinnamaldehyde (6), glycyrrhizin (7), atractylenolide III (8), atractylenolide II (9), atractylenolide I (10), and pachymic acid (11) were separated on a UPLC BEH $C_{18}$ column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $45^{\circ}C$ eluted with a gradient condition of 0.1% (v/v) formic acid in distilled water and acetonitrile. The correlation coefficient of the calibration curve of the eleven constituents was ${\geq}0.9936$. The limits of detection and quantification of the compounds 1 - 11 were 0.06 - 4.73 ng/mL and 0.17-14.20 ng/mL, respectively. Using this analytical method, the compound 11 in lyophilized YGCGT decoction extract was not detected, while the compounds 1 - 10 were detected 0.13-166.43 mg/g.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2322-2328
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• 2010

A multiple solid-phase extraction (SPE) method was used with liquid chromatography, coupled with mass spectrometry (LC/MS), for the analysis of heterocyclic amines (HCAs) in human urine. Separation efficiencies based on the pH of the mobile phase and the types of columns were compared. An amide column showed better baseline separation and narrower HCA peak widths at pH 5.0 for the mobile phase than a $C_8$ column. Each SPE step, HLB, MCX, and HybridSPE, was optimized by controlling the pH conditions. The combined method with the three SPEs effectively removed interfering species that cause ion-suppression during HCA detection. Validation of the method, performed with SIM and SRM detection, showed correlation coefficients above 0.991 in the range 0.3 - 16.7 ng/mL. Recovery rates were 45.4 - 97.3% on the $C_8$ column and 71.8 - 101.4% on the amide column, and method detection limits were 0.11 - 0.65 ng/mL on the $C_8$ column and 0.12 - 0.48 ng/mL on the amide column. This method using multiple SPEs offers significant benefits for high-throughput determination of HCAs in urine.

• CELLMED
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• v.7 no.3
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• pp.14.1-14.4
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• 2017

Rumex crispus (RC) or Cordyceps militaris (CM) has been used traditionally to treat various diseases and has been also consumed as a functional food made by humanitas medicine concept. We prepared a new herbal mixture, AST2017-01 which is mainly composed of processed (Beopje)-RC (P-RC) and -CM (P-CM). This study aims to validate marker compounds (chrysophanol and cordycepin) in P-RC and P-CM and water extracted-RC and -CM using liquid chromatography-tandem mass spectrometry. In addition, we analyzed contents of chrysophanol and cordycepin in AST2017-01. The linarites of chrysophanol and cordycepin were obtained in calibration curve with a coefficient of correlation of 0.999. The results showed that the concentrations of chrysophanol and cordycepin in P-RC and P-CM were almost 1.70 and 1.23 fold higher than that in RC and CM, respectively. Furthermore, contents of chrysophanol and cordycepin in the AST2017-01 are approximately 0.13% and 0.028%, respectively. In conclusion, these results indicate that chrysophanol and cordycepin were validated as marker compounds in the AST2017-01.

• Natural Product Sciences
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• v.20 no.3
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• pp.182-190
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• 2014

An ultra-performance liquid chromatography (UPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry (MS) method was established for quantitative analysis of twelve components, allantoin (1), morroniside (2), 5-hydroxymethyl-2-furfural (5-HMF) (3), loganin (4), coumarin (5), cinnamic acid (6), mesaconitine (7), cinnamaldehyde (8), hypaconitine (9), aconitine (10), alisol B (11), and alisol B acetate (12) in a Palmijihwang-hwan decoction. The twelve constituents were separated on a UPLC BEH C18 column ($2.1{\times}100mm$, $1.7{\mu}m$) at a column temperature of $40^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as the mobile phase. The flow rate was 0.3 mL/min and the injection volume was $2.0{\mu}L$. Calibration curves of all compounds were acquired with values of the correlation coefficient ${\geq}0.99$ within the test ranges. The limits of detection and quantification for all analytes were 0.01 - 4.53 ng/mL and 0.03 - 13.60 ng/mL, respectively. The concentrations of the compounds 1 - 9 and 12 were 72.83, 4389.00, 4859.00, 3155.17, 223.67, 33.50, 1.97, 518.00, 2.25, and $25.00{\mu}g/g$, respectively. However, compounds 10 and 11 were not detected.

• Food Science of Animal Resources
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• v.34 no.6
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• pp.749-756
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• 2014

A rapid and simple analytical method for L-carnitine was developed for infant and toddler formulas by liquid chromatography tandem mass spectrometry (LC-MS/MS). A 0.3 g of infant formula and toddler formula sample was mixed in a 50 mL conical tube with 9 mL water and 1 mL 0.1 M hydrochloric acid (HCl) to chemical extraction. Then, chloroform was used for removing a lipid fraction. After centrifuged, L-carnitine was separated and quantified using LC-MS/MS with electrospray ionization (ESI) mode. The precursor ion for L-carnitine was m/z 162, and product ions were m/z 103 (quantitative) and m/z 85 (qualitative), respectively. The results for spiked recovery test were in the range of 93.18-95.64% and the result for certified reference material (SRM 1849a) was within the range of the certificated values. This method could be implemented in many laboratories that require time and labor saving.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.747-751
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• 2000

This study was carried out to improve the analysis method of gingerol compounds from ginger (Zingiber officinale Roscoe). Pungent components of ginger were extracted by acetone and lisolated by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with LiChrosorb RP-18 column. Three homologues of gingerols were identified by HPLC-mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR). The contents of [6]-, [8]- and [10]-gingerols in three homologues identified were 635.3 mg%, 206.6 mg% and 145.7 mg% in raw ginger, and were 418.2 mg%, 142.6 mg% and 103.3 mg% in ginger paste, respectively.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.165-171
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• 2012

As a preceding study for investigating the influence of sound wave stimulus on Arabidopsis thaliana metabolomics, the polar secondary metabolomes of the plant were determined using high performance liquid chromatography coupled with tandem mass spectrometry. A total of 10 polar secondary metabolomes were characterized and quantified. Among them, 4 metabolomes, p-coumaroylagmatine isomer (7 and 8), p-coumaroylagmatine isomer (9 and 10) were identified in the plant for the first time. The validation was conducted in terms of linearity, recovery, precision, limit of detection (LOD) and limit of quantification (LOQ). The validated method was applied to the simultaneous quantification of the 10 polar secondary metabolomes.