• 한국환경농학회지
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• 제34권3호
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• pp.230-237
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• 2015

BACKGROUND: To identify the sources of inaccuracy in LC/MS/MS methods used in the routine quantitation of small molecules are described and discussed. METHODS AND RESULTS: Various UPLC coupled to triple quadrupole mass spectrometer and time of flight (TOF) were used to identify the potential sources of inaccuracy and inducing the pitfalls of qualification and quntitation during the veterinary drug residue analysis. Some of stable isotope labelled veterinary drugs, which were used as internal standards, presented "cross-talk", regardless of manufactures of mass spectrometer and types of spectrometer. Group of sulfonamides also presented inaccuracy qualification and quantitation due to the multi-residue analytical method with the same fragment ions at the close retention times. CONCLUSION: The phenomena of "cross-talk" occurring between subsequently monitored transition from stable isotope labelled and isotope non-labelled authentic chemical were identified. To prevent errors and achieve more accurate data during the analysis of small molecules by LC/MS/MS SRM method, Followings should be taken care of and kept checking; purity and concentration of stable isotope as an internal standard, prevention of carry-over during the separation in column, minimizing the ion suppression by matrix effect, identification of retention time, precursor ion and product ion, and full knowledge of data processing including smoothing and peak integration.

• Journal of Pharmaceutical Investigation
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• 제41권4호
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• pp.255-262
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• 2011

Method using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of pregabalin in plasma samples. Acquisition was performed by monitoring the transitions: m/z 160.1${\rightarrow}$142.2 for pregabalin and m/z 423.2${\rightarrow}$207.1 for losartan (as an internal standard). After cold acetonitrileinduced protein precipitation of the plasma samples, separation was performed with C18 column by isocratic mobile phase consisted of 10 mM ammonium acetate and acetonitrile (15:85, v/v). Results were linear over the concentration ranged from 0.1 to $10{\mu}g$/mL and the correlation coefficients (r) were $\geq0.99$. Intra- and inter-day precisions were $\leq6.02$ and $\leq11.04%$, respectively, and intra- and inter-day accuracies were 96.60-101.09 and 98.10-102.60%, respectively. This validated method was successfully applied to a bioequivalence study of two formulations of pregabalin, Daewoong pregabalin capsule (Daewoong Pharm. Co., Ltd.) and Lyrica$^{(R)}$ capsule (Pfizer Korea Ltd.) in twenty eight healthy Korean volunteers. The subjects received a single oral dose of each formulation (150 mg as pregabalin) in a randomized $2{\times}2$ crossover study and plasma samples were obtained from each subject at predetermined time intervals. Then, the pharmacokinetic parameters ($AUC_{0-t}$, $C_{max}$ and $T_{max}$) were calculated and statistically analyzed to assess the differences between two formulations. The 90% confidence intervals for the log-transformed data were acceptable range of log 0.8-log 1.25 (e.g., log 1.0048-log 1.0692 for AUC0-t, log 0.9142-log 1.0421 for $C_{max}$). Thus, $AUC_{0-t}$ and $C_{max}$ met the criteria of the Korea Food and Drug Administration (KFDA) for bioequivalence test indicating that Daewoong pregabalin capsule was bioequivalent to Lyrica$^{(R)}$ capsule.

• 생약학회지
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• 제46권4호
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• pp.352-364
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• 2015

The aim of this study was to quantitatively analyze for quality assessment of eighteen marker compounds, including homogentisic acid, 3,4-dihydroxybenzaldehyde, spinosin, liquiritin, hesperidin, ginsenoside Rg1, liquiritigenin, ginsenoside Rb1, glycyrrhizin, 6-gingerol, atractylenolide III, honokiol, costunolide, dehydrocostuslactone, atractylenolide II, nootkatone, magnolol, and atractylenolide I, in Hyangsayukgunja-tang using an ultra-performance liquid chromatography-electrospray ionization-mass spectrometer. The column for separation of eighteen marker components were used a UPLC BEH $C_{18}$ analytical column ($2.1{\times}100mm$, $1.7{\mu}$) and kept at $45^{\circ}C$ by gradient elution with 0.1% (v/v) formic acid in water and acetonitrile as mobile phase. The flow rate and injection volume were 0.3 mL/min and $2.0{\mu}l$, respectively. The correlation coefficient of all marker compounds was ${\geq}0.9914$, which means good linearity, within the test ranges. The limits of detection and quantification values of the all analytes were in the ranges 0.04-1.11 and 0.13-3.33 ng/mL, respectively. As a result, five compounds, homogentisic acid, 3,4-dihydroxybenzaldehyde, spinosin, liquiritigenin, and atractylenolide I, in this sample were not detected and the amounts of the 13 compounds except for the 5 compounds were $8.10-6736.37{\mu}g/g$ in Hyangsayukgunja-tang extract.

• 대한화학회지
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• 제60권2호
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• pp.118-124
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• 2016

파라벤은 화장품, 식품, 의약품 등에 첨가되는 살균성 보존제로 미생물의 성장을 억제한다. 그러나 체내에서 에스트로겐과 유사한 작용을 하는 내분비계 교란물질이며, 특히 독성물질에 민감한 영유아 및 태아에게 노출될 경우 생식기 기형, 고환암, 성조숙증 등 성장발달에 큰 영향을 미친다. 따라서 본 연구에서는 영아가 주로 섭취하는 모유에서의 파라벤 수준을 확인하기 위하여 모유 중 4가지 파라벤(methyl paraben, ethyl paraben, propyl parabne, butyl paraben)의 분석법을 확립하였다. 시료는 액체상추출(Liquid-liquid extraction, LLE)을 통하여 전처리 한 후, 액체크로마토그래피 텐덤 질량분석기(liquid chromatography tandem mass spectrometry, LC-MS/MS)를 사용하여 정량분석 하였다. 확립된 분석조건에서 얻어진 검량선의 직선성은 r² > 0.999이고, 검출한계(LOD)는 0.019~0.044 ng/mL이었다. 또한 정확도는 85.3~105.9%, 정밀도는 10% 이하의 값을 나타내었다. 10개의 모유시료 중 파라벤류의 평균농도 ± 표준편차는 MP 0.660 ± 0.519 ng/mL, EP 1.631 ± 2.081 ng/mL, PP 0.326 ± 0.320 ng/mL이었고, BP는 불검출 되었다.

• Mass Spectrometry Letters
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• 제12권4호
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• pp.200-205
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• 2021

Polynemoraline C, a pyridocoumarin alkaloid, exhibits anticholinergic, anti-inflammatory, antitumor, and antimicrobial activities. A sensitive analytical method of polynemoraline C in mouse plasma was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Polynemoraline C and ¹³C-caffeine (internal standard) in mouse plasma were extracted using a liquid-liquid extraction method coupled with ethyl acetate. This extraction method resulted in high and reproducible extraction recovery in the range of 73.49%-77.31% with no interfering peaks around the peak retention time of polynemoraline C and ¹³C-caffeine. The standard calibration curves for polynemoraline C were linear over the range of 0.5-200 ng/mL with r² > 0.985. The accuracy, precision, and the stability of the data were within acceptable limits on the FDA guideline. After intravenous and oral administration of polynemoraline C at doses of 5 and 30 mg/kg, respectively, the present method was successfully applied to the pharmacokinetic study of polynemoraline C. Polynemoraline C in mouse plasma showed a multi-exponential elimination pattern with a high volume of distribution values. This compound's absolute oral bioavailability was found to be 17.0%. Polynemoraline C's newly developed LC-MS/MS method can be used for further studies on the efficacy, toxicity, and biopharmaceutics of polynemoraline C, as well as its pharmacokinetic studies.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2023년도 임시총회 및 춘계학술대회
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• pp.62-62
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• 2023

Zanthoxylum piperitum ("chopi" in Korean) has been used as traditional medicinal plants with high anti-inflammatory, antioxidant, and antifungal activities. The aims of the study were to identify marker compounds and to investigate metabolites variation of chopi according to different parts and harvest times. Every month from June to September, chopi were harvested with three different parts: leaves, leaf-twig mixtures, twigs. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), two main marker compounds (quercitrin and quercetin-3-O-glucoside) were characterized in 70% ethanol extracts of chopi. Quantification of the two marker compounds were subsequently conducted by high performance liquid chromatography (HPLC), representing that contents of these compounds were higher in leaves and leaf-twig mixtures rather than twigs. For the comprehensive analysis of metabolites associated with production of marker compounds, 35 primary metabolites were identified using gas chromatography-mass spectrometry (GC-MS). Multivariate analysis results represented that plant parts were main contributors to the separation of chopi. However, significant differences were not observed between leaves and leaf-twig mixtures samples. The partial least square (PLS) predictive model revealed that monosaccharides (fructose, galactose, glucose, mannose, xylose) and branched-chain amino acids (isoleucine, valine, leucine) were important determinants for the production of marker compounds together with alanine, inositol, GABA, and theronic acid. This study could be extended to stabilize and utilize chopi as an industrial material, as well as to find good candidates with various nutritional traits.

• 분석과학
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• 제28권1호
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• pp.1-7
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• 2015

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco specific nitrosamine found only in tobacco products. The ability to monitor biomarker concentrations is very important in understanding environmental tobacco smoke (ETS). In this study, an efficient and sensitive method for the analysis of NNK in dust was developed and validated using liquid chromatography tandem mass spectrometry. Dust was collected with filter paper soaked in methanol. The standard solution and dust sample were diluted with 100 mM ammonium acetate and extracted using dichloromethane. Our calibration curves ranged from 25 to $10^4pg/mL$. Excellent linearity was obtained with correlation coefficient values between 0.9996 and 1.0000. The limit of detection (LOD) was 5 pg/mL ($S/N{\geq}3$) and the retention time was 10 min. The limit of quantification (LOQ) was 25 pg/mL, and the acceptance criteria was the rate of 98-103% (80-120% at levels up to $3{\times}LOQ$). The coefficient of variations (CV) was 2.8%. Accuracies determined from dust samples spiked with four different levels of NNK racurves ranged that from 25 to 104 pg/mL. Excellent linearity was obtained between 92.1% and 114%. The precision of the method was acceptable (5% of CV). The recovery rates of the whole analytical procedure at low, medium, and high levels were 105.7-116.5% for NNK. The carry-over effects during LC-MS/MS analysis were not observed for NNK. This manuscript summarizes the scientific evidence on the use of markers to measure ETS.

• 한국식품과학회지
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• 제43권5호
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• pp.544-552
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• 2011

식품 중 존재하는 PAHs를 분석하기 위해 GC-MS/MS를 이용하여 분쇄원두커피를 대상으로 15종의 PAHs를 동시분석 하였다. 전처리법은 soxhlet법, 비누화분해 후 액체-액체 추출법, 초음파후 고체-액체추출법으로 비교실험하여 재현성과 불순물제거효율이 가장 좋은 초음파 후 고체-액체 추출법을 선택하여 실험하였다. 실험법의 회수율은 PAHs종에 따라 52.6-93.3%, 검출한계는 0.002-0.1 ${\mu}g/kg$, 정량한계는 0.006-0.2 ${\mu}g/kg$로 PAHs분석에 가장 좋은 감도를 나타내는 HPLC-FLD나 GC-MS-SIM과 비슷하거나 낮은 수준의 검출한계를 나타내었다. 적합한 전처리 방법을 선택한 후 시중 유통되는 원두커피를 대상으로 15종의 PAHs 함량을 조사하였을 때 46종의 총 PAHs농도는 불검출-5.988 ${\mu}g/kg$이었다. 분쇄원두커피를 커피메이커로 추출하여 PAHs의 이행계수를 계산 한 후 WHO와 U.S.EPA에서 설정한 상대독성계수(TEF)를 근거로 음용되는 원두커피의 인체노출량(mg/kg b.w./day)을 구한 결과 $5.24{\times}10^{-8}$ mg/kg b.w./day였다.

• Mass Spectrometry Letters
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• 제2권4호
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• pp.92-95
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• 2011

Pyrophosphates are the key intermediates in the biosynthesis of isoprenoids, and their concentrations could reveal the benefits of statins in cardiovascular diseases. Quantitative analysis of five pyrophosphates, including isopentenyl pyrophosphate (IPP), dimethylallyl pyrophosphate (DMAPP), geranyl pyrophosphate (GPP), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP), was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative ionization mode. After dilution with methanol, samples were separated on a 3 ${\mu}m$ particle multi-modal $C_{18}$ column ($50{\times}2$ mm) and quantified within 10 min. The gradient elution consists of 10 mM ammonium bicarbonate and 0.5% triethylamine (TEA) in water and 0.1% TEA in 80% acetonitrile was used at the flow rate of 0.4 mL/min. Overall recoveries were 51.4-106.6%, while the limit of quantification was 0.05 ${\mu}g$/mL for GPP and FPP and 0.1 ${\mu}g$/mL for IPP, DMAPP, and GGPP. The precision (% CV) and accuracy (% bias) of the assay were 1.9-12.3% and 89.6-111.8%, respectively, in 0.05-10 ${\mu}g$/mL calibration ranges ($R^2$ > 0.993). The devised LC-MS/MS technique with the multi-modal $C_{18}$ column can be used to estimate the biological activity of pyrophosphates in plasma and may be applicable to cardiovascular events with cholesterol metabolism as well as the drug efficacy of statins.

• 분석과학
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• 제28권6호
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• pp.460-466
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• 2015

분유 내 콜레스테롤을 정량분석하기 위한 일차분석법으로 동위원소희석 질량분석법을 개발하였다. 내부표준물질로 콜레스테롤-d₄를 사용하여 분유에 첨가하였다. 분유에 지방산과 에스테르형태로 결합되어 있는 콜레스테롤을 자유 콜레스테롤로 바꾸어주기 위해 비누화과정을 수행하였다. 비누화과정은 반응온도, 반응시간, 사용한 KOH의 농도에 따라서 최적화하였으며, 그 결과로 분유시료 0.1 g에 대해 70 ℃에서 180 분 동안 8 M의 KOH 0.8 mL를 첨가하여 반응을 진행시키는 최적화조건을 확립하였다. 이와 같은 조건으로 실험을 진행하여 재현성은 0.23%, 확장불확도는 95%의 신뢰범위에서 1.9%로 추정되었다. 확립된 동위원소희석 질량분석법의 유효화를 위해 분유내에서 콜레스테롤의 인증값을 가지는 NIST SRM을 측정하였고 이 결과가 인증값과 불확도 범위내에서 일치하는 것을 확인하였다.