• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.3
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• pp.23-46
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• 1999

LC/MS는 HPLC의 분리능과 질량분석기의 화합물의 확인 능력을 결합시킨 기기이다. 여기서 사용되는 이온화 방법은 GCJMS에서 사용되어지는 전자이온화법(electron ionization, EI)이나, 화학이온화법(chemical ionization, CI)은 부적당하기 때문에 최근 개발되어진 연성 이온화법의 대표적인 고속원자폭격식(Fast atom bombardment, FAB)이나 전기분무이온화식 (electrospray ionization, ESI) 등이 사용되고 있다. 이중 전기분무이온화법은 고속원자폭격법에서 사용되는 매트릭스를 사용하지 않기 때문에 매트릭스 이온의 부재로 인한 낮은 바탕 신호, 오래 지속되면서 안정된 초기 이온 전류, 샘플링의 용이성, HPLC와의 더 좋은 호환성 등의 장점을 제공한다. 이러한 전기분무이온화 방법은 극성이 매우 크거나 휘발성이 낮은 물질로 보통의 EI나 CI 이온화 방법으로 분석이 어려운 물질들을 분석할 수 있다. 또한 열에 불안정하거나 분자의 분자량이 다른 단백질 등의 분석도 가능하다. 이러한 LC/ESI/MS 방법을 이용하여 열에 불안정하고 극성이면서 분자량이 커서 GC/MS 펄의 분석이 어려운 기능성 화장품 원료로 주목받고 있고 생체에 존재하는 지질 성분으로 알려진 레시틴과 세라마이드의 분석이 가능함을 소개하고 분리와 동시에 그 분자량과 구조에 대한 정보를 빠르게 얻을 수 있음을 소개하였다.

• Mass Spectrometry Letters
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• v.2 no.3
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• pp.65-68
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• 2011

The effects of column length and particle size on the efficiency of separation and characterization of phospholipids (PLs) are investigated using nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MS-MS). Since PLs are associated with cell proliferation, apoptosis, and signal transduction, it is of increasing interests in lipidomics to establish reliable analytical methods for the qualitative and quantitative profiling of PLs related to biomarker development in adult diseases. Due to the complexity of PLs, the preliminary separation of PLs is necessary prior to MS analysis. In this study, length of capillary column and the particle size of reversed phase ($C_{18}$) packing materials are varied to find a reliable condition for the high speed and high resolution separation using 8 PL standard mixtures. From experiments, it was found that a capillary column of nLC-ESI-MS-MS analysis for PL mixtures can be minimized to a 5 cm long pulled tip column packed with 3 ${\mu}m$ $C_{18}$ particles without losing resolution.

• 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 $548.13{\mu}g/g$.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.737-744
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• 2007

An isotope dilution-liquid chromatography/tandem mass spectrometric method was developed as a candidate reference method for the accurate determination of acrylamide in potato chips, starch-rich foodstuff cooked at high temperature. Sample was spiked with 13C3-acrylamide and then extracted with water. The extract was further cleaned up with an Oasis HLB solid-phase extraction (SPE) cartridge and an Oasis mixed-phase cation exchange (MCX) SPE cartridge. The extract was analyzed by using LC/ESI/Tandem MS in positive ion mode. LC with a medium reversed-phase (C4) column was optimized to obtain adequate chromatographic retention and separation of acrylamide. MS was operated to selectively monitor [M+H]+ ions of the analyte and its isotope analogue at m/z 72 and m/z 75, respectively. Sample was also analyzed by the LC/MS with selectively monitoring the collisionally induced dissociation channels of m/z 72 → m/z 55 and m/z 75 → 58. Compared to the LC/MS chromatograms, the LC/MS/MS chromatograms showed substantially reduced background chemical noises coming from solvent clusters formed during ESI spray processes and interferences from sample matrix. Repeatability and reproducibility studies showed that the LC/MS/MS method is a reliable and reproducible method which can provide a typical method precision of 1.0% while the LC/MS results are influenced by chemical interferences.

• Analytical Science and Technology
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• v.23 no.5
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• pp.457-464
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• 2010

The analytical method of four pharmaceuticals (virginiamycin, erythromycin, tylosin and cimetidine) in drinking water was developed. Effective simultaneous sample clean-up and extraction by solid-phase extraction (SPE) using HLB cartridge prior to LC/ESI-MS/MS analysis were performed. A linear correlation observed in the calibration curves for drinking water in the range of 0.01~2.0 ng/mL showed above $r^2$=0.995. Absolute recovery was in the range of 64.7~118.1% (except cimetidine (37.7~48.1%)). Limit of detection (LOD) and limit of quantitation (LOQ) in spiked drinking water matrix were in the range of 1.6~74.8 pg/mL and 5.5~249.7 pg/mL, respectively. The established method can be used to determine low pg/mL levels of pharmaceuticals in the drinking water.

• Mass Spectrometry Letters
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• v.5 no.1
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• pp.1-11
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• 2014

Lipids play important roles in biological systems; they store energy, play a structural role in the cell membrane, and are involved in cell growth, signal transduction, and apoptosis. Phospholipids (PLs) in particular have received attention in the medical and lipidomics research fields because of their involvement in human diseases such as diabetes, obesity, atherosclerosis, and many cancers associated with lipid metabolic disorders. Here I review experimental strategies for PL analysis based on nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nLC-ESI-MSn). In particular, discussed are lipid extraction methods, nanoflow LC separation of PLs, effect of ionization modifiers on the ESI of PLs, influence of chain lengths and unsaturation degree of acyl chains of PLs on MS intensity, structural determination of the molecular structure of PLs and their oxidized products, and quantitative profiling of PLs from biological samples such as tissue, urine, and plasma in relation to cancer and coronary artery disease.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.302-307
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• 2012

The herb of Artemisia capillaris in Chinese medicine is used to treat hepatic diseases. In this research, qualitative analysis was performed using a UPLC/Q-TOF-ESI-MS/MS method for rapid identification of phenolic substances from A. capillaris: three caffeoylquinic acids (chlorogenic acid, 3,5-di-O-caffeoylquinic acid, and 4,5-di-O-caffeoylquinic acid), three flavonoids (hyperoside, isorhamnetin 3-O-robinobioside and quercetin) and three prenylated coumarins (6,8-diprenylumbelliferone, cedrelopsin and osthol) were identified. The three prenylated coumarins have not been reported from A. capillaris.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.157-165
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• 2008

In the previous study, the anti-oxidant activity of oxtract/fraction of Sueada aspparagoides(SA) and the stability test for the cream containing SA extract were investigated respectively[1,2]. In this study, the components of SA extract were analyzed by TLC, HPLC, and LC/ESI-MS/MS, $^1H$-NMR. TLC chromatogram of ethyl acetate fraction of SA extract revealed 5 bands $(SA1{\sim}SA5)$. HPLC chromatogram of aglycone fractions obtained from deglycoylation reaction of ethyl acetate fraction showed 2 bands (SAA 2 and SAA 1), which were identified as quercetin (composition ratio, 16.88%) and kaempferol (83.12%) in the order of elution time. Among 5 bands of TLC chromatogram, 4 bands $(SA2{\sim}SA5)$ also were Identified as kaempferol-3-O-glucoside (SA 2), quercetin-3-O-glucoside (SA3), kaempferol-3-O-rutinoside (SA 4), quercetin-3-O-rutinoside (SA 5) by LC/ESI-MS/MSMS/MS. respectively. The spectrum generated for SAA 1 by LC/ESI-MS/MS in the negative ion mode also gave the ion corresponding to the deprotonated aglycone $[M-H]^-$ (285m/z), the $^1H$-NMR spectrum contained signals [${\delta}$ 6.19 (1H, d, J=1.8Hz, H-6), ${\delta}$ 6.44 (1H, d, J=1.8Hz, H-8), ${\delta}$ 6.92 (2H, d, J=9.0Hz, H-3', 5'), ${\delta}$ 8.04 (2H, d, J=9.0Hz, H-2', 6', thus SAA 1 was identified as kaempferol. SAA 2 yielded the deprotonated agycone ion $[M-H]^-$ (301m/z), $^1H$-NMR spectrum showed signals [${\delta}$ 6.20 (1H, d, J=2.0Hz, H-6), ${\delta}$ 6.42 (1H, d, J=2.0Hz, H-8), ${\delta}$ 6.90 (1H, d, J=8.6Hz, H-5'), ${\delta}$ 7.55 (1H, dd, J=8.6, 2.2Hz, H-6'), ${\delta}$ 7.69 (1H, d, J=2.2Hz, H-2', thus SAA 2 was Identified as quercetin. In conclusion, with the anti-oxidant activity and the stability test reported previously, component analysis of SA extracts could be applicable to new cosmeceuticals.

• Journal of environmental and Sanitary engineering
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• v.19 no.4 s.54
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• pp.25-33
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• 2004

Acrylamide, difficult to analyze by GC and GC/MS due to the polarity and low volatility, was analyzed by LC/ESI/MS in the study. Acrylamide its(molecular weight 71amu) showed m/z=72 $(M+H)^+$ and high peak intensity at 22V in SIR mode. The mass spectrum ratios of acrylamide for qualitative identification had m/z=72 in precursor ion and m/z=55 in products ion, respectively. Those ratios at 30V in SIR mode ranged from 1: 1.4 to 1:1.17 despite various acrylamide concentrations. The ion intensity ratios of acrylamide $(m/z=72,\; [M+H]^+)$ to acrylamide isotopes $(m/z=73,\;[M+H]^+)$ ranged from 100 : 3.57 to 100 : 3.92. The results verified theoretical mass spectrum ratio that was 100:3.82. The linearity of standard calibration curve was y : 520.584x + 1815.26 with $r^2=0.99.$ In quality assurance and quality control, the recovery rate ranged from 81.64 percent to 90.97 percent and relative standard deviation was less than $10\%$ with 5 repeated injections at individual standard calibration solutions. The method was applied to analyze acrylamide in food at grocery stores. Snacks made of potatoes showed the highest acrylamide concentration followed by products made of French fries, wheat, and corn.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.90-97
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• 2017

Androgenic anabolic steroids (AASs) are synthetic derivatives of testosterone with a common structure containing cyclopentanoperhydrophenanthrene nucleus. Their use enhances the muscle building capacity and is beneficial during performance. The AASs are one of the most abused group of substances in horse doping. Liquid chromatography tandem mass spectrometry ($LC/MS^n$) has been successfully applied to the detection of anabolic steroids in biological samples. However, the saturated hydroxysteroids viz: nandrolone, $5{\alpha}-estrane-3{\beta}$, $17{\alpha}-diol$ exhibit lower detection responses in electrospray ionisation (ESI) because of their poor ionisation efficiency. To overcome this limitation pre-column chemical derivatization has been introduced to enhance their detection responses in $LC-ESI-MS^n$ analysis. The aim of present study was to develop a sensitive method for identification and confirmation of nandrolone and its metabolite in horse urine incorporating pre-column derivatization using picolinic acid. The method consists of extraction of targeted steroid conjugates by solid phase extraction (SPE). The eluted steroid conjugates were hydrolysed by methanolysis and free steroids were recovered with liquid-liquid extraction. The resulting steroids were derivatized to form picolinoyl esters and identification was done using LC-ESI-MS/MS in positive ionization mode. The picolinated steroid adduct enhanced the detection levels in comparison to underivatized steroids.