An automatic phenolic compounds analyzer is presented. The system performs online magnetic-stirring-assisted dispersive liquid-liquid microextraction before multisyringe chromatography (MSC) using a monolithic Chromolith Flash RP-18e column. The extraction behavior of the following phenolic pollutants: phenol, 2-nitrophenol, 4-nitrophenol, 2-chlorophenol, 2,4-diclorophenol, and 2,4,6-trichlorophenol, has been studied. A critical comparison of extractants (tributyl phosphate, acetonitrile, hexane, and 1-chlorobutane) and disperser solvents (acetone, acetonitrile, ethanol, methanol, 1-propanol, and 2-propanol) was made. Tributyl phosphate and acetonitrile were chosen as the extractant and the disperser solvent, respectively, since these showed the best performance. Phenols were online back-extracted into NaOH and neutralized before multi-isocratic chromatographic separation. The proposed analyzer can be applied for wide linear working ranges, i.e., between 40 and 20,000 μg L(-1). The precision of the developed system has been proved, with maximum values for the intraday and interday precision of 4.4 % and 5.2 %, respectively, expressed as relative standard deviation, and high preconcentration factors (9.3-10.5) for most of the compounds studied. The method developed was successfully applied to natural water samples.
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http://dx.doi.org/10.1007/s00216-015-8464-1 | DOI Listing |
Chemosphere
December 2024
Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research, 08034 Barcelona, Spain. Electronic address:
The assessment of persistence of organic pollutants in seawater is limited by the lack of user-friendly, quick protocols for assessing one of their main sinks, degradation by marine bacteria. Here we present an experimental workflow to identify organic pollutants degradation, taking organophosphate esters flame retardants and plasticizers (OPEs-FR-PL), as a model family of synthetic chemicals released into the marine environment that are particularly widespread due to their persistence and semi-volatile nature. The proposed novel workflow combines culture-dependent techniques, solvent demulsification-dispersive liquid-liquid microextraction, with quantitative liquid chromatography coupled with mass spectrometry analyses in order to identify marine bacterial isolates with the potential to degrade OPEs-FR-PL in the marine environment.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Research Center of New Material and Green Chemistry, Khazar University, 41 Mehseti Street, Baku AZ1096, Azerbaijan; Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
This paper introduces an innovative technique for extracting pesticides from herbal infusions using a core-shell magnetic adsorbent (i.e., Cu-BTC@FeO) where achieving a notable enrichment factor for the target pesticides by coupling with a dispersive liquid-liquid microextraction method.
View Article and Find Full Text PDFJ Chromatogr A
December 2024
College of Pharmacy, Harbin University of Commerce, Harbin 150076, China. Electronic address:
Traditional Chinese medicine (TCM) is a treasure of China and a crucial part of traditional medicine in the world, particularly in many oriental countries. TCM is the core and basis of traditional medicine in clinical practice for numerous diseases, and performs important function in nutraceuticals and dietary supplements. However, it is extremely difficult to extract each active ingredient from TCM to elucidate the mechanism of TCM clinical efficacy due to numerous compounds in TCM, especially trace compounds.
View Article and Find Full Text PDFMolecules
November 2024
Institute for Nanotechnology and Water Sustainability, College of Science, Engineering, and Technology, University of South Africa, Florida Science Campus, Roodepoort 1710, South Africa.
Due to their antibacterial and antifungal properties, parabens are commonly used as biocides and preservatives in food, cosmetics, and pharmaceuticals. Parabens have been reported to exist in various water matrices at low concentrations, which renders the need for sample preparation before their quantification using analytical techniques. Thus, sample preparation methods such as solid-phase extraction (SPE), rotating-disk sorptive extraction (RDSE), and vortex-assisted dispersive liquid-liquid extraction (VA-DLLE) that are commonly used for parabens extraction and preconcentration have been discussed.
View Article and Find Full Text PDFFoods
November 2024
Department of Analytical Chemistry, Nutrition and Food Science, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
The occurrence of carbonyl compounds and volatile organic compounds (VOCs) in adult formulas is a critical issue in product safety and quality. This research manuscript reports the determination of targeted and untargeted carbonyl compounds and VOCs in adult formulas stored at different temperatures (room temperature, 4 °C, and 60 °C) over one month. Gas chromatography-mass spectrometry was utilized for the sample analysis.
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