• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.513-519
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• 2004

A sensitive method for quantification of pinaverium bromide in human plasma was established using liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS). Glimepiride was used as internal standard. Pinaverium bromide and internal standard in plasma sample were extracted using tert-butylmethylether(TBME). A centrifuged upper layer was then evaporated and reconstituted with mobile phase of acetonitrile-5 mM ammonium formate (80/20, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS with multiple reaction monitoring (MRM) mode, pinaverium and glimepirde were detected without severe interference from human plasma matrix. Pinaverium produced a protonated precursor ion $([M+H]^+)$ at m/z 510.3 and a corresponding product ion at m/z 228.9. Internal standard produced a protonated precursor ion $([M+H]^+)$ at m/z 491.5 and a corresponding product ion at m/z 352.0. Detection of pinaverium bromide in human plasma was accurate and precise, with limit of quantitation at 0.5 ng/ml. The method has been successfully applied to bioavailability study of pinaverium bromide tablet in Korean healthy male volunteers. Pharmacokinetic parameters such as $AUC_t,\;C_{max},\;T_{max},\;K_{el}\;and\;t_{1/2}$ were calculated.

• 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.

• Analytical Science and Technology
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• v.15 no.6
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• pp.574-579
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• 2002

A sensitive and easy high performance liquid chromatograph (HPLC) / electrospray ionization (ESI)-mass spectrometric (MS) method has been developed for the quantitative and qualitative analyses of acarbose and its metabolites. After plasma samples were simply filtered with a syringe filter, the filtered plasma was analyzed by LC/MS. The standard calibration curve for acarbose was linear ($r^2=0.9963$) over the concentration range $0.1{\sim}10{\mu}g/m{\ell}$ in plasma. The metabolite component-I and II, which were metabolized by the ${\alpha}$-amylase and ${\beta}$-amylase, were found also by in vitro incubation. The developed method can be utilized to study acarbose and the other carbohydrates.

• Analytical Science and Technology
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• v.14 no.5
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• pp.384-391
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• 2001

In this study, a new quantitative analytical method has been developed for the rapid determination of acylcarnitines and amino acids in human blood using electrospray ionization / tandem mass spectrometry (ESI-MS/MS). Acylarmitines and amino acids were analyzed by tandem mass spectrometry after conversion to their butylesters through treatment with 3N butanolic hydrogen chloride. Acylcrnitines were analyzed using precursor 85 ion scan and alanine, valine, leucine/isoleucine, methionine, phenylalanine, tyrosine, aspartic acid and glutamic acid were analyzed using neutral loss 102 scan, ornitine and citrulline were analyzed neutral loss 119 scan, glycine was analyzed using neutral loss 56 scan, arginine was analyzed using neutral loss 161 scan and argininosuccinic acid was analyzed product ion 459 scan. This method reduced sample preparation time compared to that with conventional amino acid analyzer and liquid chromatography, with high sensitivity and good reproducibility.

• YAKHAK HOEJI
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• v.60 no.1
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• pp.15-20
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• 2016

Globotriaosylsphingosine (lyso Gb3) is considered as one of the biomarkers for Fabry disease. A rapid and simple UPLC-MS/MS method was developed for the determination of reliable biomarker, lyso Gb3. Total analytical procedure takes only 15 min including sample preparation and MS/MS analysis. Limit of detection was 0.85 ng/ml (S/N=3). The calibration curve was linear over the range of 2.0~400.0 ng/ml ($R^2=0.9999$). Inter-day and intra-day assay accuracy were 93.4~100.6% (RSD, 0.6~6.0%) and 97.5~100.7% (RSD, 3.6~5.2%). Absolute recoveries of 97.6~98.6 showed excellence of a new analytical method. The method was applied to human and mice urines, proved the suitability for the quantification of lyso-Gb3 for screening, diagnosis and therapeutic monitoring of Fabry disease patients.

• 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.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.1996-2000
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• 2009

Alkali metal salts were introduced to enhance the ionization efficiency of glucose and maltooligoses in electrospray ionization-mass spectrometry (ESI-MS). A mixture of the same moles of glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, and maltoheptaose was used. Salts of lithium, sodium, potassium, and cesium were employed as the cationizing agent. The ionization efficiency varied with the alkali metal cation types as well as the analyte sizes. Ion abundance distribution of the [M+$cation]^+$ ions of the carbohydrates varied with the fragmentor voltage. The maximum ion abundance at low fragmentor voltage was observed at maltose, while the maximum ion abundance at high fragmentor voltage shifted to maltotriose or maltotetraose for Na, K, and Cs. Variation of the ionization efficiency was explained with the hydrated cation size and the binding energy of the analyte and alkali metal cation.

• 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.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3151-3155
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• 2010

This study was performed to develop analytical methods to better understand the properties and reactivity of petroleum, which is a highly complex organic mixture, using high-resolution mass spectrometry and statistical analysis. Ten crude oil samples were analyzed using negative-mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Clustering methods, including principle component analysis (PCA), hierarchical clustering analysis (HCA), and k-means clustering, were used to comparatively interpret the spectra. All the methods were consistent and showed that oxygen and sulfur-containing heteroatom species played important roles in clustering samples or peaks. The oxygen-containing samples had higher acidity than the other samples, and the clustering results were linked to properties of the crude oils. This study demonstrated that clustering methods provide a simple and effective way to interpret complex petroleomic data.