A novel approach for dispersive liquid-liquid microextraction based on the use of deep eutectic solvent as a disperser was presented for the first time. The procedure was automated based on an in-syringe flow system coupled with UV–Vis detection and demonstrated by the determination of chromium (VI) in beverages. This analytical task was used as a proof-of-concept example. The automated extraction procedure involved the aspiration of aqueous sample into a syringe pump with homogeneous mixture of extraction solvent (1-oсtanol) and deep eutectic solvent (tetrabutylammonium bromide – formic acid) containing color-forming reagent (1,5-diphenylcarbazide). This led to decomposition of deep eutectic solvent in aqueous phase resulting in dispersion of extraction solvent, oxidation of 1,5-diphenylcarbazide to 1,5- diphenylcarbazone in the presence of chromium (VI), and formation of colored chromium (III) complex with 1,5-diphenylcarbazone and its fast extraction. In this case composition of deep eutectic solvent played a key role for analyte extraction. Tetrabutylammonium bromide promoted mass transfer between aqueous phase and the extraction solvent droplets as a salting out agent, bromide ion acted as an ion-pare agent for analyte complex extraction, formic acid provided required pH value for analyte complex formation. Under the optimal conditions the limit of detection, calculated from a blank test based on 3s, was 0.2 μg L−1. The automated dispersive liquid-liquid microextraction using deep eutectic solvent as disperser can be considered as an available, efficient, rapid and environmentally friendly sample pretreatment approach.

Original languageEnglish
Article number120209
Number of pages7
JournalTalanta
Volume206
DOIs
StatePublished - 1 Jan 2020

    Research areas

  • Beverages, Chromium (VI), Deep eutectic solvent, Disperser solvent, Dispersive liquid-liquid microextraction, In-syringe flow system, Limit of Detection, Prunus avium/chemistry, Solvents/chemistry, Quaternary Ammonium Compounds/chemistry, Spectrophotometry, Ultraviolet, Drinking Water/analysis, Food Contamination/analysis, Syringes, Fruit and Vegetable Juices/analysis, Carbonated Beverages/analysis, Liquid Phase Microextraction/instrumentation, Malus/chemistry, 1-Octanol/chemistry, Chromium/analysis, Formates/chemistry, PRECONCENTRATION, TANDEM-MASS-SPECTROMETRY, SPECTROPHOTOMETRIC DETERMINATION, SOLIDIFICATION, CHROMATOGRAPHY, EXTRACTION, SPECIATION, PESTICIDES, CR(VI), WATER SAMPLES

    Scopus subject areas

  • Analytical Chemistry

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