A surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvent.

An effective and simple surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvents is presented for the first time. The developed procedure involved two stages: (i) an isolation of dyes from a solid-phase food sample into a micellar solution of the primary amine; (ii) a preconcentration of the extracted dyes into the supramolecular solvent phase generated from the obtained micellar solution under a coacervation process. The microextraction procedure was applied for the determination of synthetic dyes in confectionery, dried fruits, and spices samples. The supramolecular solvent formed from aqueous micelle aggregates of 1-octylamine due to coacervation induced by thymol provided maximum extraction recovery values for synthetic dyes. In the proposed two-stage extraction procedure the micellar solution of primary amine was a media for analytes isolation from solid-phase and their followed preconcentration.

Supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound: Liquid phase microextraction of sulfonamides.

A phenomenon of supramolecular solvents formation in aqueous solutions containing primary amine and monoterpenoid compound is presented for the first time. A novel supramolecular solvent-based liquid phase microextraction was developed. In an aqueous phase primary amine formed isotropic solution due to formation of amphiphile supramolecular assembly. The phase separation was achieved by a coacervation process. The monoterpenoid phenol (thymol) acted as a coacervation agent and induced spontaneous in situ formation of tiny supramolecular solvent droplets. The applicability of the proposed microextraction procedure was demonstrated for the separation of sulfonamides from biological fluids (human plasma and serum). An obtained composition of supramolecular solvent (1-decylamine, thymol, water) promoted satisfactory extraction of polar analytes from aqueous phase. The calibration graphs were linear over the concentration ranges of 0.06-50 mg L-1 for sulfamethoxazole, sulfamethazine and sulfapyridine. The limit of detection calculated from the blank tests based on 3σ was 0.02 mg L-1 for all analytes. The total analysis time was 15 min.

Cobalt-doped hydroxyapatite nanoparticles as a new eco-friendly catalyst of luminol-H2O2 based chemiluminescence reaction: Study of key factors, improvement the activity and analytical application.

In this study, a novel catalyst based on hydroxyapatite doped by cobalt for chemiluminescence reaction of luminol oxidation by H2O2 was suggested for the first time. The catalyst nanoparticles were synthesized by a hydrothermal method and characterized by various methods including density functional theory calculations. The impact of nanoparticles sizes, surface composition, contact efficiency and crystallinity on chemiluminescence intensity were investigated. The maximum chemiluminescence intensity was obtained for polycrystalline nanoparticles. This phenomenon was studied in detail and applied for chemiluminescence analysis for the first time. The chemiluminescence determination of sulfonamides as model analytes was considered. The sensing was based on sulfonamides-dependent quenching of the chemiluminescence intensity in the presence of novel catalyst existed as an aqueous suspension.