• 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.

• 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.35 no.4
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• pp.1133-1138
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• 2014

Ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI- MS/MS) provides a high-speed method to screen a large number of samples for small molecules with specific properties. In this study, UPLC-ESI-MS/MS with multiple reaction monitoring (MRM) was employed to screen urinary phospholipid (PL) content for biomarkers of prostate cancer. From lists of urinary PLs structurally identified using nanoflow LC-ESI-MS/MS, 52 PL species were selected for quantitative analysis in urine samples between 22 cancer-free urologic patients as controls and 45 prostate cancer patients. Statistical treatment of data by receiver operating characteristic (ROC) analysis yielded 14 PL species that differed significantly in relative concentrations (area under curve (AUC) > 0.8) between the two groups. Among PLs present at higher levels in prostate cancer urine, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) constituted the major head group PLs (3 PCs and 7 PIs). For technical reasons, PL species of low abundance may be underrepresented in data from UPLC-ESI-MS/MS performed in MRM mode. However, the proposed method enables the rapid screening of large numbers of plasma or urine samples in the search for biomarkers of human disease.

• 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.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.290.1-290.1
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• 2003

Oxidative DNA damage has been associated with many disease. Quantation of DNA adducts is considered to be a useful biomarker of oxidative DNA damage because its formation can also be induced by oxidative stress. Extensive efforts have been taken to identify the analytical methods for minimizing the artifactual formation of oxidative DNA damage. We have done direct analysis of DNA adducts using LC/ESI-MS without urine sample extraction. (omitted)

• 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.

• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.693-698
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• 2017

The quality control of natural products is principal key to guarantee the Good Manufacturing Practices (GMP) and Good Clinical Practices (GCP) for the functional food, pharmaceuticals and cosmeceuticals in the industry. In this study, we examined the quantitative analysis of berberine as marker substance of Coptidis Rhizoma by high performance liquid chromatography-photodiode array detector (HPLC-DAD). The HPLC method was validated and met all the requirements for the quality control analysis recommended by FDA and ICH. The berberine was separated on a Xterra $C_{18}$ column ($5{\mu}m$, $4.6{\times}250mm$) using mobile phase consisting of distilled water and acetonitrile with $KH_2PO_4$ (3.4 g) and $Na_2SO_4$ (1.7 g). Calibration curve of berberine has been estimated (y = 42293.47x-41589 with the correlation coefficient 0.9999). The amount of berberine was calculated as 4.25%. And berberastine, palmatine, columbamine, jatrorrhizine, epiberberine, berberine and coptisine in the Coptidis Rhizoma were identified by high performance liquid chromatography - electrospray ionization-mass spectrometer (HPLC-ESI-MS) method.

• 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.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.372-379
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• 2007

A high-performance liquid chromatography-electrospray ionization (HPLC-ESI) tandem MS was developed for the rapid and simultaneous determination of forbidden medicines in dietary supplements. Thirteen medicinal components such as PDE-5 inhibitors and their analogues, and the newly identified dimethylsildenafil and xanthoanthrafil, were included in this study. After tentative standardization of molecular ions in both polarities using thirteen references on the mass spectrometer, with ESI-continuous infusion via the syringe pump method, the relative intensity of the ions present in the resulting spectra was quantitatively compared. From the results, the ion mode was selected depending on each reference's characteristics. A HPLC method coupled with the ESI mode was developed considering the matrix effect and interference depending on the type of sample. The validation test of the developed method was followed by carrying out precision, accuracy, recovery, sensitivity and linearity, etc. The method showed sufficiently high sensitivity, reproducibility, and specificity, and produced 4 times faster results when compared with the existing HPLC/UV method for the determination of forbidden compounds in dietary supplements.