The current routes to couple dispersive liquid-liquid microextraction with capillary electrophoresis are the evaporation of water immiscible extractants and the back-extraction of analytes. In this study, a new methodology for this combination using water-in-oil microemulsion electrokinetic chromatography coupled with normal stacking mode on-line sample concentration was developed to analyze chlorophenols in water samples. The analytes were extracted with tributyl phosphate and the extractant dilution (3×) was directly injected into an electrophoresis buffer (7.7 cm) containing 5% sodium dodecyl sulfate, 78% 1-butanol, 2% 1-heptane, and 15% sodium acetate solution (pH 8.0). This proposed method is very simple and convenient compared to the conventional procedures. The key parameters affecting separation and concentration were systematically optimized. Under the optimized conditions, dispersive liquid-liquid microextraction contributed an enrichment factor of 45-50, and the overall sensitivity improvement was 312-418-fold. Limits of detection between 1.4 and 3.0 ng/mL and limits of quantification between 4.5 and 10.2 ng/mL were achieved. Acceptable repeatability lower than 3.0% for migration time and 9.0% for peak areas were obtained. The developed method was successfully applied for analysis of the chlorophenols in real water samples.
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http://dx.doi.org/10.1002/jssc.201700175 | DOI Listing |
J Chromatogr A
January 2025
School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, 450001, China; Henan Key Laboratory of Cereal and Oil Food Safety and Nutrition, Zhengzhou, 450001, China. Electronic address:
Food safety problem caused by aflatoxins (AFs) has become a major concern worldwide. However, due to the complexity of food matrices and the low concentration of analytes, the accurate and sensitive determination of AFs and their precursors in the biosynthetic pathway is extremely challenging, so the development of efficient sample preparation techniques has been urgently required. This paper reviews the recent advances in sample preparation based on some emerging extraction media for the determination of AFs and their precursors in different food samples, including ionic liquids (ILs) and IL-based composites, metal-organic frameworks (MOFs) and covalent organic frameworks (COFs).
View Article and Find Full Text PDFSoft Matter
January 2025
Department of Mathematics, National Institute of Technology Durgapur, Durgapur-713209, India.
The present article deals with the modulation of oscillatory electroosmotic flow (EOF) and solute dispersion across a nanochannel filled with an electrolyte solution surrounded by a layer of a dielectric liquid. The dielectric permittivity of the liquid layer adjacent to supporting rigid walls is taken to be lower than that of the electrolyte solution. Besides, the aforesaid liquid layer may bear additional mobile charges, , free lipid molecules, charged surfactant molecules , which in turn lead to a nonzero charge along the liquid-liquid interface.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong SAR 99999, China.
A low-molecular-weight compound whose structure strikes a fine balance between hydrophobicity and hydrophilicity may form coacervates via liquid-liquid phase separation in an aqueous solution. These coacervates may encapsulate and convoy proteins across the plasma membrane into the cell. However, releasing the cargo from the vehicle to the cytosol is challenging.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia.
Designing molecular receptors that bind anions in water is a significant challenge, and an even greater difficulty lies in using these receptors to remove anions from water without resorting to the hazardous liquid-liquid extraction approach. We here demonstrate an effective and synthetically simple strategy toward these goals by exploiting ion-pair assembly of macrocycles. Our anion binding ensemble consists of an octa-chloro tetra-urea macrocyclic anion receptor (ClTU), which forms water-dispersible aggregates, and a tetra-cationic fluorescent dye 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin (TMPyP4), which provides Coulombic stabilization and fluorescence reporting of anion binding in an ion-pair assembly.
View Article and Find Full Text PDFMolecules
January 2025
Department of Environmental Chemistry and Bioanalytics, Gagarina 7, Faculty of Chemistry, Nicolaus Copernicus University, 87-100 Torun, Poland.
Bisphenols may negatively impact human health. In this study, we propose the use of HPLC-FLD for the simultaneous determination of bisphenols in pericardial fluid samples collected from patients with coronary artery disease undergoing coronary artery bypass surgery. For sample preparation, a fast, simple, and "green" DLLME method was used, achieving mean recovery values in the range of 62%-98% with relative standard deviations between 2% and 6% for all analytes.
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