Search results for " MS"

Efficient Production of Isoflavonoids by Astragalus membranaceus Hairy Root Cultures and Evaluation of Antioxidant Activities of Extracts

2014

In this study, Astragalus membranaceus hairy root cultures (AMHRCs) were established as an attractive alternative source for the efficient production of isoflavonoids (IF). A. membranaceus hairy root line II was screened as the most efficient line and was confirmed by PCR amplification of rolB, rolC and aux1 genes. Culture parameters of AMHRCs were systematically optimized, and five main IF constituents were quali-quantitatively determined by LC-MS/MS. Under optimal conditions, the total IF accumulation of 34 day old AMHRCs was 234.77 μg/g dry weight (DW). This yield was significantly higher compared to that of 3 year old field grown roots (187.38 μg/g DW). Additionally, in vitro antioxidan…

Ultra-high-pressure liquid chromatography tandem mass spectrometry method for the determination of 9 organophosphate flame retardants in water samples

2016

Few methods are available for comprehensive organophosphate flame retardants (PFRs) detection in water and wastewater. Gas chromatography has been employed previously, but this approach is less selective, not amenable for use with deuterated standards and can suffer unfavorable fragmentation. Ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-QqQ-MS/MS) has become the most promising platform, already applied successfully for analysis of selected PFRs in some environmental matrices like water and wastewater. However, the presence of some interferences from the dissolvent, the equipment and the used materials should be taken into account. The procedure involves: The fir…

Multi-mycotoxin analysis in North African semolina samples using a modified QuEChERS-based extraction procedure and HPLC–MS/MS

2014

Quick determination of Glyphosate and AMPA at sub µg/L in drinking water by direct injection into LC-MS/MS

2021

Abstract A sensitive, simple and quick method for the determination of glyphosate (Gly) and its degradation product, Aminomethyl phosphonic acid (AMPA), in water through ion chromatography coupled to quadrupole-linear ion trap mass spectrometry has been developed. Sample treatment was based on direct injection and acquisition was implemented in both MS2 and MS3 modes. The LoQs of the method were 0.03 µ/L for both Gly-and AMPA. The recoveries were between 91 and 118% and RSD was lower than 15%. The developed methodology was applied on 436 water samples.

A LC/MS/MS method for the simultaneous quantification of free and masked fumonisins in maize and maize-based products

2008

An LC-ESI-MS/MS method for the simultaneous detection of the main fumonisins and their hydrolysed derivatives is described, allowing for a simplified sample preparation without previous clean up. The method has a very low quantification limit (10 µg/kg for FB1, 12 µg/kg for FB2 and FB3, 70 µg/kg for HFB1, HFB2 and HFB3 in maize flour) and a very good recovery for all the analytes. The method has been applied to check several maize-based foods for the presence of free and bound forms of fumonisins, the latter being determined after alkaline hydrolysis as hydrolysed derivatives. Bound fumonisins were found to be present not only in thermally treated maize-based products but also in mild proc…

Rīgas pilsētas salūta radītā gaisa piesārņojuma izvērtēšana, raksturojot aerosolu daļiņās

2017

Rīgas pilsētas salūta radītā gaisa piesārņojuma izvērtēšana, raksturojot aerosolu daļiņas. Guļa A., zinātniskā vadītāja Dr. ķīm., docente Osīte A. Maģistra darbs, 44 lappuses, 16 attēli, 14 tabulas, 43 literatūras avoti, 4 pielikumi. Latviešu valodā. Darbā ir apkopota informācija par pirotehnikas izstrādājumu sastāvu, uguņošanas radīto gaisa piesārņojumu ar smalkajām aerosolu daļiņām un to analīzes iespējām. Eksperimentāli veikta gaisa aerosolu daļiņu frakcionēšana. Realizēta smalkās un rupjās frakcijas daļiņu paraugu masas un skaita koncentrāciju noteikšana gan ikdienā, gan uguņošanas epizožu laikā. Uz filtra uztvertie gaisa aerosolu daļiņu paraugi metālisko elementu analīzei ar ICP-MS sag…

Comparison and improvement of the existing methods for the determination of aflatoxins in human serum by LC-MS/MS

2010

Aflatoxins are toxic metabolites of some Aspergillus flavus, A. parasiticus and A. nomius strains that occur in many foods and feeds. Aflatoxin B1 is the most abundant and toxic member of the family, and it is also the most potent hepatocarcinogen known. In order to estimate the potential human health risk of aflatoxin B1, it is useful to measure its blood concentration. In this work a rapid liquid chromatography coupled to mass spectrometry (LC-MS/MS) method for the simultaneous determination of aflatoxins B1, B2, G1 and G2 and its metabolites, aflatoxins M1 and M2 in human serum, is proposed. Small serum volumes have been used and the extracts have been obtained without any clean-up proce…

Comparative assessment of three extraction procedures for determination of emerging Fusarium mycotoxins in pasta by LC–MS/MS

2013

Abstract A new rapid, sensitive, reproducible and reliable method was developed for the quantitative determination of enniatins A, A1, B and B1, beauvericin and fusaproliferin in dry and fresh pasta by liquid chromatography-triple quadrupole-tandem mass spectrometry. A comparative study of different rapid and economical extraction procedures was performed for the extraction of these mycotoxins in pasta. For this purpose, three different approaches were studied during the extraction step (Ultra-Turrax, ultrasonic bath and microwave). Optimal extraction conditions were reached using Ultra-Turrax with acetonitrile for 3 min without purification step. The chromatographic separation of the six m…

Multimycotoxin LC-MS/MS Analysis in Tea Beverages after Dispersive Liquid-Liquid Microextraction (DLLME).

2017

The aim of the present study was to develop a multimycotoxin liquid chromatography tandem mass spectrometry (LC-MS/MS) method with a dispersive liquid-liquid microextraction procedure (DLLME) for the analysis of AFs, 3aDON, 15aDON, NIV, HT-2, T-2, ZEA, OTA, ENNs, and BEA in tea beverages and to evaluate their mycotoxin contents. The proposed method was characterized in terms of linearity, limits of detection (LODs), limits of quantification (LOQs), recoveries, repeatability (intraday precision), reproducibility (interday precision), and matrix effects to check suitability. The results show LODs in the range of 0.05-10 μg/L, LOQs in the range of 0.2-33 μg/L, and recoveries in the range of 65…

Online Solid-Phase Extraction LC-MS/MS: A Rapid and Valid Method for the Determination of Perfluorinated Compounds at Sub ng·L-1Level in Natural Water

2018

In this research paper, we report a method able to detect perfluorinated compound at pg·L−1 levels in superficial and underground water samples. An online solid phase extraction HPLC-MS/MS method was developed for the analysis of 12 perfluoroalkyl acids (PFASs). The method is based on injection of 5000 µL of water sample in SPE online WAX column followed by chromatography separation and mass spectrometry determination. SPE online elution was performed by water + 0.05% NH4OH and methanol + 0.05% NH4OH, while separation of target compounds was achieved within 10 min by Gemini chromatographic column operating from 1 to 12 pH range and using a mixture of water-methanol + 0.05% NH4OH. Sub ng·L−1…