摘要 :
A new computational tool is proposed here for tentatively identifying major (UV quantifiable) flavone/ flavonol glycoside peaks of high performance liquid chromatogram (HPLC)-diode array detection (DAD)-tandem mass spectrometry (M...
展开
A new computational tool is proposed here for tentatively identifying major (UV quantifiable) flavone/ flavonol glycoside peaks of high performance liquid chromatogram (HPLC)-diode array detection (DAD)-tandem mass spectrometry (MS/MS) profiles based on a MATLABbased script implementing an in-house algorithm. The HPLC- DAD-MS/MS profiles of red onion, Chinese lettuce, carrot leaf, and celery seed extracts were analyzed by the proposed computer-aided screening method for identifying possible flavone/flavonol glycoside peaks from the HPLC-UV and MS total ion current (TIC) chromatograms. The number of identified flavone/flavonol glycoside peaks of the HPLC-UV chromatograms is four, four, six, and nine for red onion, Chinese lettuce, carrot leaf, and celery seed, respectively. These results have been validated by human experts. For the batch processing of nine HPLC-DAD-MS/MS profiles of celery seed extract, the entire script execution time was within 15 s while manual calculation of only one HPLC-DAD-MS/ MS profile by a flavonoid expert could take hours. Therefore, this MATLAB-based screening method is able to facilitate the HPLC-DAD-MS/MS analysis of flavone/flavonol glycosides in plants to a large extent.
收起
摘要 :
Residual fluoroquinolone levels in animal foods retailed in Korea were monitored according to the method outlined in Korea Food Code using HPLC-FLD and HPLC-ESI-MS/MS for confirmation. The optimum ion transitions were 360->316, 34...
展开
Residual fluoroquinolone levels in animal foods retailed in Korea were monitored according to the method outlined in Korea Food Code using HPLC-FLD and HPLC-ESI-MS/MS for confirmation. The optimum ion transitions were 360->316, 342 m/z for enrofloxacin, 332->314, 288 m/z for ciprofloxacin, 320->301, 230 m/z for norfloxacin, 334->315, 290 m/z for pefloxacin, 362->318, 261, 334 m/z for ofloxacin, and 262->201, 126 m/z for flumequin. Enrofloxacin, ciprofloxacin and norfloxacin residues were found in 12out of 388 samples. These antibiotics were only found in chicken samples, while no residues were found in beef, pork, milk and egg samples. Using this monitoring method, detection rates of 3.1, 1.3, and 0.3% were obtained for enrofloxacin, ciprofloxacinand norfloxacin, respectively. The levels of enrofloxacin, ciprofloxacin and norfloxacin detected in food samples ranged from 0.01 to 0.73 mg/kg in 12 samples, 0.01-0.03 mg/kg in 5 samples, and 0.12 mg/kg in only a sample, respectively.
收起
摘要 :
An analytical HPLC-MS screening methodology has been developed to improve preparative RP-HPLC-MS purifications in medicinal chemistry laboratories. Although several approaches have been previously described to optimize analytical ...
展开
An analytical HPLC-MS screening methodology has been developed to improve preparative RP-HPLC-MS purifications in medicinal chemistry laboratories. Although several approaches have been previously described to optimize analytical separations, none of them met our needs for the optimization of preparative conditions. Our screening protocol is based on searching among several orthogonal conditions to find the optimum preparative separation. Five different buffer conditions, from low to high pH, two organic solvents, acetonitrile and methanol, and five stationary phases of different polarities and characteristics were used. The orthogonality of the system was demonstrated using both, a standard mixture and mixtures from synthesis. To carry out the screening one of the analytical " open access" HPLC-MS systems was modified to perform the analytical screening while maintaining the open-access functionality for synthesis reaction monitoring. A software tool for automated sample programming and data reporting was also developed.
收起
摘要 :
Dimethyltin dichloride (DMTC) is widely used as a heat stabilizer in manufacturing the polyvinyl chloride. We previously reported a case of acute DMTC poisoning with neurological manifestations very similar to trimethylated tin JM...
展开
Dimethyltin dichloride (DMTC) is widely used as a heat stabilizer in manufacturing the polyvinyl chloride. We previously reported a case of acute DMTC poisoning with neurological manifestations very similar to trimethylated tin JMT) encephalopathy, based on results of speciation analysis of methylated tins in the patient's urine with use of a combination of high performance liquid chromatography and inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), which yielded peaks corresponding to DMT and TMT. In this study, we developed an analytical method to confirm TMT in urine using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and found TMT molecular ion in the patient's urine.
收起
摘要 :
The aim of this research was to study the processes of biotransformation of selenium in plants such as garlic, radish sprouts and sunflower sprouts via identification of selenium-containing compounds as metabolites of inorganic se...
展开
The aim of this research was to study the processes of biotransformation of selenium in plants such as garlic, radish sprouts and sunflower sprouts via identification of selenium-containing compounds as metabolites of inorganic selenium using mass spectrometry. Speciation analysis of selenium in extracts from plant samples was performed with the use of hyphenated high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method. Matching the retention times of sample compounds with standards allowed identification of Se-methylselenocysteine, selenomethionine, gamma-glutamyl-Se-methylselenocysteine and inorganic SeO32-. However, registered chromatograms included additional Se-82 signals which couldn't be identified due to the lack of standards.
收起
摘要 :
A rapid, sensitive and specific method for the determination of cepharanthine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was described. Cepharanthine and the int...
展开
A rapid, sensitive and specific method for the determination of cepharanthine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was described. Cepharanthine and the internal standard (I.S.), telmisartan, were extracted from human plasma by methanol to precipitate the protein. A centrifuged upper layer was then evaporated and reconstituted with 100μL methanol. Chromatographic separation was performed on an AGILENT XDB-C_8 column (150mm×2.1mm, 5.0μm, Agilent, USA) using a gradient mobile phase with 1mmol/L ammonium acetate in water with 0.05% formic acid and methanol. Detection and quantitation was performed by MS/MS using electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ion mode. The most intense [M+H]~+ MRM transition of cepharanthine at m/z 607.3→365.3 was used for quantitation and the transition at m/z 515.5→276.4 was used to monitor telmisartan. The calibration curve was linear within the concentration range of 0.5-200.0ng/mL (r=0.9994). The limit of quantification (LOQ) was 0.5ng/mL. The extraction recovery was above 81.1%. The accuracy was higher than 92.3%. The intra- and inter-day precisions were less than 9.66%. The method was accurate, sensitive and simple and was successfully applied to a pharmacokinetic study after single intravenous administration of 50mg cepharnthine in 12 healthy Chinese volunteers.
收起
摘要 :
Sofrito is a key component of the Mediterranean diet, a diet that is strongly associated with a reduced risk of cardiovascular events. In this study, different Mediterranean sofritos were analysed for their content of polyphenols ...
展开
Sofrito is a key component of the Mediterranean diet, a diet that is strongly associated with a reduced risk of cardiovascular events. In this study, different Mediterranean sofritos were analysed for their content of polyphenols and carotenoids after a suitable work-up extraction procedure using liquid chromatography/ electrospray ionisation-linear ion trap quadrupole-Orbitrap-mass spectrometry (LC/ESI-LTQ-Orbitrap-MS) and liquid chromatography/electrospray ionisation tandem triple quadrupole mass spectrometry (LC/ESi-MS-MS). In this way, 40 polyphenols (simple phenolic and hydroxycinnamoylquinic acids, and flavone, flavonol and dihydrochalcone derivatives) were identified with very good mass accuracy (＜ 2 mDa), and confirmed by accurate mass measurements in MS and MS~2 modes. The high-resolution MS analyses revealed the presence of polyphenols never previously reported in Mediterranean sofrito. The quantification levels of phenolic and carotenoid compounds led to the distinction of features among different Mediterranean sofritos according to the type of vegetables (garlic and onions) or olive oil added for their production.
收起
摘要 :
Ziziphus jujuba and Ziziphus nummularia are two important species of the genus Ziziphus. Both plants offer great commercial value and are consumed as food around the world and used for their medicinal values such as anti-inflammat...
展开
Ziziphus jujuba and Ziziphus nummularia are two important species of the genus Ziziphus. Both plants offer great commercial value and are consumed as food around the world and used for their medicinal values such as anti-inflammatory, antioxidant and hepatoprotective activities. Comprehensive chemical profiling of Z. jujuba and Z. nummularia was done through identification of major metabolites using HPLC-QTOF-MS/MS and quantification of eight analytes using HPLC-IonTrap-MS/MS analysis. A total of 53 compounds were identified from their high-resolution mass spectra in both positive and negative ionization modes. Among these, 52 compounds were found to be present in Z. jujuba, and 45 in Z nummularia. Chemometric analysis was also performed to assess the distribution of identified compounds and to determine how the obtained data can be used to discriminate between the two species. Moreover, a method for the quantification of eight analytes including, 6 '''-feruloylspinosin (1), apigenin (2), apigenin-7-O-glucoside (3), catechin (4), jujuboside A (5), jujuboside B (6), luteolin (7) and quercetin (8) was developed. The method expressed excellent accuracy with less than 3% error and good reproducibility with less than 4% RSD. The limit-of-detection (LOD) was also found to be very low ranging between 0.06 ng/mL to 4.10 ng/mL while limit-of-quantitation (LOQ) values were in the range of 0.17 ng/mL to 12.42 ng/mL. The analyte concentrations were found to be varying from 1.32 mg/kg to 645.76 mg/kg in both species. The developed method was used to identify and quantify marker compounds in fruit and whole plant samples of both species and in their herbal products as well. The present work is unprecedented, as there is no such extensive study targeting fruits, leaves and herbal formulations together using high-resolution techniques. The study will provide great utility in drug discovery, in taxonomical identification of these plants and to develop quality control protocols for their herbal formulations. (C) 2019 Elsevier B.V. All rights reserved.
收起
摘要 :
Es wird eine Methode zur Bestimmung von Ochratoxin A in Gewürzen nach Reinigung über Immunoaffinitatssaulen und anschliessender LC-MS/MS beschrieben. Ochratoxin A (OTA) ist ein Mykotoxin, das von Schimmelpilzen der Gattungen Asp...
展开
Es wird eine Methode zur Bestimmung von Ochratoxin A in Gewürzen nach Reinigung über Immunoaffinitatssaulen und anschliessender LC-MS/MS beschrieben. Ochratoxin A (OTA) ist ein Mykotoxin, das von Schimmelpilzen der Gattungen Aspergillus und Penicillium auf Getreide, Kaffee, Gewürzen und anderen Lebensmitteln gebildet werden kann. Der Schimmelpilzbefall und damit die potenzielle Bildung von OTA wird durch ungünstige Temperatur und Feuchtigkeitsbedingungen wahrend der Ernte, der Weiterverarbeitung,der Trocknung, Lagerung und des Transportes begünstigt. OTA ist ein Mykotoxin mit karzinogenen, nephrotoxischen, teratogenen, immunotoxischen und moglicherweise neurotoxischen Eigenschaften.
收起
原文获取