• 대한유전성대사질환학회지
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• 제15권2호
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• pp.59-64
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• 2015

사람의 신체내에서 주로 존재하는 lactate는 L-lactate로서 몇몇 선천성대사이상과 관련하여 증가된다. 최근 2형 당뇨병(type 2 diabetes)과 만성적인 염증성 위장질환(inflammatory bowel disease)과 관련하여 증가되는 D-lactate를 L-lactate와 분리해야 하는 요구도가 높아졌다. 이에 액체크로마토그래프-탠덤질량 분석기를 사용하여 소변 내 D-, L-lactate를 분리하는 방법을 확립하였으며, 분석시간과 정밀성, 정확성, 특이성 등에서 신뢰성 있는 방법임을 확인하였다.

• 한국동물위생학회지
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• 제30권1호
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• pp.13-21
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• 2007

An atmospheric pressure chemical ionization (APcI) LC/MS/MS method was developed for the simultaneous analysis of fluoroquinolones (norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin) residues in eggs. The spiked and blank samples were extracted from whole eggs using 50mM phosphate buffer (pH 7.4). The extract was cleaned up by passage though $Oasis^{(R)}$ MAX extraction cartridge for solid-phase extraction followed by elution with 4% formic acid in methanol. The extract of sample was separated on a Waters $Atlantis^{TM}$ $dC_{18}$ reversed-phase column ($4.6{\times}150mm,\;5{\mu}m$) and analyzed by APcI positive mode mass spectrometry. The mobile phase consists of aqueous 0.2% nonafluoropentanoic acid (NFPA) and methanol. Multiple reaction monitoring (MRM) using the precursor to product ion combinations of m/z $320\;{\dashrightarrow}\;302,\;332\;{\dashrightarrow}\;314,\;360\;{\dashrightarrow}\;342$ and m/z $358\;{\dashrightarrow}\;340$ were used to quantify norfloxacin (NOR), ciprofloxacin (CIP), enrofloxacin (ENR) and danofloxacin (DAN), respectively. The limits of quantification (LOQ) were 7.8ppb for NOR, 8.5ppb for CIP, 8.9ppb for ENR, and 4.8ppb for DAN. Average recoveries of fortified sample at levels of 0.025 to 0.1 ppm were estimated 71.29% for NOR, 75.27% for CIP, 85.51% for ENR and 81.22% for DAN. These results could be applied for the confirmation and quantification in eggs.

• 한국수산과학회지
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• 제44권1호
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• pp.45-49
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• 2011

As a first step toward identifying a new method for testing sea snail tissue for toxins, and thus prevent food poisoning due to the ingestion of contaminated snails, we measured the tetramine [$(CH_3)_4N^+$] contents of sea snails from the Korean coast using both liquid chromatography-tandem mass spectrometry (LC-MS/MS) and ion chromatography. For tetramine tested, good linearity ($r^2$ = 0.9996) was observed between the amounts in the injected samples and the peak areas of standard toxins, which ranged from 0.1 to 100 ng. The recovery (%) of tetramine from spiked tissue and mid-gut gland samples ranged from 84.0 to 95.3%. The quantitative results for tetramine using this method were in good agreement with the theoretical values. LC-MS/MS has both high sensitivity and selectivity, which makes it possible to measure trace quantities of tetramine in samples.

• 약학회지
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• 제60권3호
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• pp.112-117
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• 2016

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of caffeine in forensic aqueous sample. The centrifuged sample ($100{\mu}l$) was diluted 50-fold with distilled water. The diluted sample ($400{\mu}l$) was then diluted further with $200{\mu}l$ of 0.1% formic acid solution and $400{\mu}l$ of acetonitrile containing 500 ng of caffeine-(3-methyl-$^{13}C_3$) prior to LC-MS/MS analysis. The mobile phase was composed of 0.1% formic acid in distilled water (A) and acetonitrile (B). Chromatographic separation was performed by using a Zorbax SB-C18 ($100mm{\times}2.1mm$ i.d., $3.5{\mu}m$) column and caffeine was eluted within 1.1 min. Linear least-squares regression with a 1/x weighting factor was used to generate a calibration curve with the coefficients of determination ($r^2=0.9983$). The lower limit of quantification was $25ng/ml$ for the analyte. The process efficiency was 98.6~100.1%. Intra- and inter-day precisions were not more than 2.1% and 1.7%, while intra- and inter-day accuracies were ranged from -6.8 to 4.5%, respectively. The suitability of the method was examined by analyzing unknown forensic aqueous samples.

• 약학회지
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• 제52권2호
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• pp.93-100
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• 2008

A liquid chromatographic method with tandom spectrometric detection (LC/MS/MS) for the simultaneous determination of doxifluridine and its active metabolite, 5-fluorouracil (5-FU) was developed over the concentration range of $5{\sim}2000$ ng/ml, respectively. Doxifluridine, 5-FU and internal standard, 5-chlorouracil (5-CU), were extracted from liver and intestine tissue via protein precipitation. Acetonitrile was used as the extraction solvent and the supernatant was evaporated and reconstructed in mobile phase. Optimum chromatographic separation was achieved on a Agilent Zorbax $C_{18}$ ($100\;mm{\times}2.1\;mm$, $3.5\;{\mu}m$) column with mobile phase run in isocratic with methanol : water (20 : 80, v/v). The flow rate was 0.2 ml/min with total cycle time of 5 min. The lower limit of quantification was validated at 5.0 ng/ml of liver and intestine tissue, for both doxifluridine and 5-FU, respectively. The intra-day and inter-day precision and accuracy of quality control (QC) samples were <11% coefficient of variation and <7% relative error from theoretical concentration for both analytes. In addition, the special designed stability study was performed, because the metabolism of doxifluridine occurs spontaneously even in ice bath for monkey liver. The stability of doxifluridine in liver and intestine of monkey and beagle dog was compared. It was found that bioanalytical validation could not be performed for the monkey liver; however, beagle dog's liver has relatively low speed of metabolism compared to monkey liver and instead of monkey liver, beagle dog's liver could be used for the validation. Bioanalytical validation could be performed in monkey intestine. Eventually, this developed method for liver and intestine will be useful in support of the toxicokinetic and pharmacokinetic studies of doxifluridine and 5-FU.

• 생약학회지
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• 제51권4호
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• pp.270-277
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• 2020

This study analyzed mycotoxins, aflatoxin B1, B2, G1, G2, fumonisin B1, B2, ochratoxin A and zearalenone, using LC-MS/MS and conducted risk assessment on 54 samples of seeds distributed in SeoulYangnyeongsi and the management status of extramural herbal dispensary facility. The matched calibration showed a good linearity as observed in 6 concentration levels(r2>0.999) as a result of method validation applied with Arecae semen. Limits of detection(LOD) and quantification(LOQ) were in the range of 0.02-0.11 ㎍/kg and 0.08-0.34 ㎍/kg, respectively. Recoveries also estimated, ranging from 65.1-99.7% with relative standard deviation(RSD) 0.5-6.3%. As a result of the method on 54 samples, mycotoxins were detected in 16 samples. Among them, two Thujae semen showed a degree of concentration that exceeded the aflatoxin specification. In the risk assessment, the human exposure safety standard values were calculated as ADI(Acceptable Daily Intake) for aflatoxin B1, fumonisin and zearalenone. Ochratoxin A was calculated as PTWI(Provisional Tolerable Weekly Intake). The MOE(Margine of Exposure) of aflatoxin B1 was in the range of 40.36-3536.88. And no items exceeded 100% in %TDI(Tolerable Daily Intake) and %TWI(Tolerable Weekly Intake) of fumonisin, zearalenone and ochratoxin A.

• Journal of Pharmaceutical Investigation
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• 제37권4호
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• pp.223-227
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• 2007

A rapid, simple and sensitive LC/MS/MS method for the determination of lercanidipine in human serum was validated and applied to the pharmacokinetic study of lercanidipine. Lercanidipine and internal standard, amlodipine, were extracted from human serum by liquid-liquid extraction with hexan-isoamyl alcohol (100: 1, v/v) and analyzed on a $Symmetry^{(R)}$ MS $C_{18}$ column with the mobile phase of acetonitrile-0.2% aqueous formic acid (70: 30, v/v). Using MS/MS with multiple reaction monitoring (MRM) mode, lercanidipine and amlodipine were detected without severe interferences from human serum matrix. Lercanidipine produced a protonated precursor ion ($[M+H]^+$) at m/z 612.3 and a corresponding product ion at m/z 280.0. Internal standard produced a protonated precursor ion ($[M+H]^+$]) at m/z 409.0 and a corresponding product ion at m/z 238.0. The ruggedness of this method was investigated using quality control (QC) samples. This method showed linear response over the concentration range of 0.05-20 ng/mL with correlation coefficient greater than 0.999. The lower limit of quantitation using 0.5 mL of serum was 0.05 ng/mL, which was sensitive enough for pharmacokinetic studies. The overall accuracy of the developed method ranged from 85.51 to 112.2% for lercanidipine with overall precision (% C.V.) being 3.56-13.1%. This method showed good ruggedness (within 15% C.V.) and was successfully applied for the analysis of lercanidipine in human serum samples for the pharmacokinetic studies, demonstrating the suitability of the method.

• Mass Spectrometry Letters
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• 제15권1호
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• pp.49-53
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• 2024

Ceramide is a lipid in which sphingoid bases and fatty acids are linked by amide bonds. As a marker of skin disease in the human stratum corneum, its disease-causing and therapeutic effects have been partially confirmed, and it is therefore an important element in commercially available cosmetic formulations. However, structural diversity caused by differences in the chain length, number, and location of hydroxyl groups makes quality control difficult. In this study, a method was established to separate different ceramide species using reversed-phase LC-MS/MS and thus enable qualitative evaluation. Separation of four standards was achieved within a short retention time, and the accuracy and sensitivity of the method were demonstrated by the low limit of detection (LOD) calculated based on the calibration curve showing linearity, with R² > 0.994. After verification of reproducibility and reliability through intra- and inter-day analyses, the efficiency of the method was confirmed through analysis of commercial cosmetic raw materials.

• 분석과학
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• 제22권1호
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• pp.65-74
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• 2009

옻나무는 아시아지역 전역에 주로 분포하며 예로부터 도료 및 약용 식물로 많이 사용되어져 왔었다. 특히 우리나라에서 재배되는 옻나무가 그 기능이 더욱 우수하다고 알려져 있는데 그 원인은 명확히 밝혀진 바가 없다. 우선 옻나무에서 우루시올의 추출을 위하여 나무는 soxhlet의 방법으로, 옻나무 추출물은 liquid-liquid extraction (LLE)의 방법을 이용하여 각각의 우루시올을 추출하였으며, 추출한 각 성분들은 high performance liquid chromatography/ultraviolet & visible detector system (HPLC/UV-Vis)에 먼저 적용하여 분리의 최적 조건을 찾았다. 그리고 각 성분에 대한 정확한 분석을 위하여 reverse phase liquid chromatography on-line electro spray ionization mass spectrometer (LC-MS/MS)를 이용하였으며 이를 바탕으로 분자량에 따른 성분 확인과 함량을 연구하였다. 이동상의 조건으로는 methanol : 0.1% formic acid : DDW를 929 : 1 : 70의 부피비로 사용하여 최적의 분리 조건을 얻었다. 이러한 LC의 조건으로 다시 LC-MS/MS에 적용하여 MRM의 방식으로 각각의 함량을 구할 수 있었다. 분자량에 따라 총 4종류의 우루시올 동종체들이 존재를 확인하였다. 본 연구를 통하여 한국산 옻나무 추출물의 경우 외국산 옻나무의 것 보다 곁사슬에 이중결합이 많은 우루시올 동종체의 함량이 많이 존재하며 그 전체적 비율이 높은 것으로 밝혀졌다.

• 한국식품위생안전성학회지
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• 제31권1호
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• pp.15-20
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• 2016

LC-MS/MS를 이용한 말라카이트 그린 유효성 검증결과 결정계수($R^2$)가 0.9996이상으로 높은 직선성을 보여주었으며 회수율은 어종에 따라 69.8%에서 93.9%범위를 보였다. 검출한계는 $0.013{\mu}g/kg$, 정량한계는 $0.038{\mu}g/kg$으로 CODEX의 가이드라인을 만족하였다. 수거된 어류 200건에서 말라카이트 그린을 분석한 결과, HPLC-DAD로는 1건이 검출되었으나, LC-MS/MS로 분석시 검출률은 18.5%였다. 본 연구 결과, LC-MS/MS를 이용한 말라카이트 그린 분석법이 우리나라에서 많이 소비되는 담수어종에서 분석에 적합하며, 1건을 제외한 모든 시료에서 식품공전의 잔류허용기준 이하로 말라카이트 그린이 검출되어서 안전한 것으로 나타났다. 다만 식품공전의 검출한계 이하로 말라카이트 그린이 검출되는 빈도가 18.5%임을 볼 때, 지속적으로 감시하고 모니터링 할 필요가 있음을 시사한다.