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Lee, Myoung Eun,Ko, Keon-hee,Park, Na-Hyun,Lee, Wonwoong,Yoo, Hye Hyun,Lee, Jeongmi,Choi, Yong Seok,Hong, Jongki Elsevier 2018 Microchemical Journal Vol.143 No.-
<P><B>Abstract</B></P> <P>Analysis of marine biotoxins in high-lipid bivalves has several limitations due to the coexistence of lipid matrices, low biotoxin concentrations, and the different physiochemical properties of the various biotoxins. In this study, a sensitive and reliable method to simultaneously determine six diarrhetic shellfish poisoning (DSP) toxins (five acidic and one neutral biotoxins) in oysters and mussels was developed based on UHPLC-MS/MS-multiple ion reaction monitoring (MRM) using time segment polarity switching. For effective sample pretreatment, three protocols including syringe filtration, Strata™-X solid phase extraction (SPE), and freezing lipid filtration combined with SPE (FLF + SPE) were evaluated, and FLF + SPE method was shown to be the most effective with high lipid removal efficiency. Aging effects of the UHPLC mobile phase on MS detection sensitivity and retention time shift of DSP toxins were carefully examined. The developed method provided good recoveries ranging from 81.0 to 119.6%, showing no significant matrix effect and assay was linear with coefficients of determination above R<SUP>2</SUP> > 0.99 for all analytes. Validation tests using a certified reference material (CRM) and spiking DSP toxins (OA and DTX-1 at 1.07 μg/g, and DTX-2 at 0.86 μg/g) showed this method to be acceptable, with a relative standard deviation of <0.17% and recovery ranging from 87.29 to 109.97%. Finally, the established method was successfully applied to quantify DSP toxins in 40 oyster and mussel samples collected from Korean fishery markets, ensuring sea food safety.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Three extraction protocols were examined for determining lipophilic DSP toxins in high-lipid bivalves </LI> <LI> SPE combined with FLF was shown the best analytical performance in terms of cleanup efficiency, matrix effect, and sensitivity of DSP toxins. </LI> <LI> Simultaneously determined different polarity DSP toxins in a single run using time segment polarity switching mode </LI> <LI> Validated quantification of trace DSP toxins through CRM analysis and spiking experiments </LI> <LI> Successful monitoring the levels of DSP toxins in high-lipid bivalves </LI> </UL> </P>
Lee, Wonwoong,Park, Na Hyun,Ahn, Tae-Beom,Chung, Bong Chul,Hong, Jongki Elsevier 2017 Journal of chromatography Vol.1526 No.-
<P>Development of a reliable analytical method of neurochemicals in biological fluids is important to discover potential biomarkers for the diagnosis, treatment and prognosis of neurological disorders. However, neurochemical profiling of biological samples is challenging because of highly different polarities between basic and acidic neurochemicals, low physiological levels, and high matrix interference in biological samples. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method combined with in situ selective derivatization for comprehensive profiling of 20 neurochemicals in urine was developed for a wide range of neurochemicals. In situ selective derivatization greatly improved the peak capacity on a reversed-phase C18 column and sensitive mass detection in LC-ESI-MS/MS-positive ion mode due to reduction of the distinct physicochemical properties between acidic and basic neurochemicals. The MS/MS spectra of neurochemicals exhibited specific ions, such as losses of amine, methanol, or methyl formate molecules from protonated molecules, enabling selection of appropriate multiple reaction monitoring (MRM) ions for selective and sensitive detection. The developed method was validated in terms of linearity, limit of detection (LOD) and limit of quantification (LOQ), precision, accuracy, and recovery. The correlation coefficients (R-2) of calibration curves were above 0.9961. The ranges of LODs and LOQs were 0.1-3.6 ng/mL and 0.3-12.0 ng/mL, respectively. The overall precision and accuracy were 0.52-16.74% and 82.26-118.17%, respectively. The method was successfully applied to simultaneously profile the metabolic pathways of tyrosine, tryptophan, and glutamate in Parkinson's disease patient urine (PD, n = 21) and control urine (n = 10). Significant differences (P <= 0.01) between two groups in the activity of phenylethanolamine N-methyltransferase (PNMT) and alcohol dehydrogenase (ADH) were observed. In conclusion, this method provides reliable quantification of a wide range of neurochemicals in human urine and would be helpful for finding biomarkers related to specific neuronal diseases. (C) 2017 Elsevier B.V. All rights reserved.</P>
Wonwoong Lee(이원웅),You Lee Kim,Jongki Hong 한국분석과학회 2021 학술대회논문집 Vol.2021 No.11
Short-chain fatty acids (SCFAs) are produced by bacterial fermentation from dietary fiber, permeate through the intestinal cell membrane, and are distributed in the human body via blood circulation. Since absorbed SCFAs, such as acetic acid, propionic acid, and butyric acid, could introduce into tricarboxylic acid cycle (TCA cycle) in the host cells, the relationships between SCFAs and TCA cycle intermediates might influence to energy metabolism, homeostasis, and numerous disease conditions in the human body. For this reason, the information on profile changes between SCFAs and TCA cycle intermediates is required to unveil pathological mechanisms of intractable diseases including cancers. However, due to different characteristics between mono-carboxylate structured SCFAs and di-/tri- carboxylate structured TCA cycle intermediates, it demands a sophisticated analytical method. Generally, a base pairing method would be effective to decrease loss of volatile SCFAs, whereas high pH level could decrease recoveries of TCA cycle intermediates by base decarboxylation. Therefore, to improve loss of volatile SCFAs and base decarboxylation of TCA cycle intermediates, in this study, a tetra-alkyl ammonium paring method was developed. Based on the optimized ammonium paring method, SCFAs and TCA cycle intermediates were effectively extracted from human plasma without significant loss. Furtheremore, to assess gastric disorders with dysbiosis, alterations of SCFAs and TCA cycle intermediates in human plasma with gastric disorders were analyzed using gas chromatography-tandem mass spectrometry (GC-MS/MS) with N-methyl-N-tert-butyldimethylsilyltrifluoroacetamide (MTBSTFA) derivatization. This study provides a comprehensive profiling method to determine SCFAs and TCA cycle intermediates in human plasma and would be helpful to discover the etiological mechanisms of gastric diseases based on profiling of host-gut microbiome co-metabolic pathways.
Lee, Wonwoong,Park, Na Hyun,Lee, Yong Chan,Kim, Ki-Hyun,Hong, Jongki Elsevier 2018 Trends in analytical chemistry Vol.106 No.-
<P><B>Abstract</B></P> <P>Neurochemicals are mainly distributed in the central nervous system, and related to various neurological functions and disorders. Because neurochemicals are biosynthesized and metabolized through multiple pathways, it is difficult to understand the overall nervous system or to diagnose neurological disorders based on certain neurochemical levels. Therefore, to learn more about the nervous system and neurological disorders, metabolomics approaches should be used to profile the metabolic pathways of neurochemicals. To date, the neurochemical profiling has been pursued by various methods, especially including mass spectrometry (MS) coupled with conventional chromatographic techniques, which can sensitively and selectively determine numerous neurochemicals in biological samples. Nevertheless, the development of chromatographic MS-based analytical platforms to profile neurochemicals in biological samples has faced several challenges. This review was organized to help characterize neurochemicals using descriptions of the basic procedures (sample preparation and chromatographic MS detection). Moreover, we describe clinical applications and performance evaluation of these techniques.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Advances and challenges in neurochemical profiling of biological samples are discussed. </LI> <LI> Recent trends of biological sample preparation methods are presented. </LI> <LI> Clinical applications of neurochemical profiling techniques are summarized. </LI> <LI> Analytical performance of advanced mass spectrometry-separation methods is discussed. </LI> </UL> </P>