Primary amine citrate-based supramolecular designer solvent: Preconcentration of ochratoxin A for determination in foods by liquid chromatography

• Published in: Analytica chimica acta 2024-01, Vol.1285, p.341991-341991, Article 341991
• Main Authors: Pochivalov, Aleksei, Fedorova, Anastasia, Yakimova, Nina, Safonova, Evgenia, Bulatov, Andrey
• Format: Article
• Language: English
• Subjects: Chromatography, High Pressure Liquid; Citrates; Citric Acid; Food; HPLC-FLD; Liquid Phase Microextraction - methods; Micelles; Ochratoxin А; Primary amine citrate; Quaternary Ammonium Compounds; Solvents - chemistry; Supramolecular solvent-based microextraction; Tetrabutylammonium bromide
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2023.341991

Supramolecular solvents are nanostructured liquids that are separated from colloidal solutions of amphiphilic compounds as a result of self-assembly of amphiphiles and coacervation under changing conditions. They are considered to be designer solvents as their properties can be tailored to a specific analytical task by controlling the conditions of their formation (amphiphile, coacervation inducer, medium, concentration of components). The discovery of new extraction systems based on supramolecular solvents and their application to relevant analytical tasks are of great importance for the advancement of environmentally-friendly sample preparation. A novel green liquid-phase microextraction approach involving in situ formation of 1-octylamine citrate followed by preconcentration of ochratoxin A from aqueous extract of food sample in supramolecular solvent droplets was developed. The extraction system was carefully characterized. The density of the solvent allowed it to be to retrieved from the extraction system by its solidification. The alkaline nature of the obtained extract allowed the use of acetic acid for its dissolution instead of more toxic organic solvents followed by high-performance liquid chromatography with fluorometric detection. An excellent extraction recovery of 99 % and a satisfactory enrichment factor of 8.3 were achieved. The limit of detection was 0.5 μg kg−1, while the calibration plot was linear over the range of 1.5–50 μg kg−1. Cereal and roasted coffee bean samples were successfully analyzed with a relative bias less than 20 %. In the present work, a phenomenon of supramolecular solvent formation based on primary amine citrate was presented for the first time. Tetrabutylammonium bromide was investigated as a coacervation agent in an extraction system, and possible interactions responsible for its ability to induce phase separation in a micellar solution of primary amine citrate were described. The critical micelle concentration of 1-octylamine citrate in aqueous solution of tetrabutylammonium bromide was firstly determined. [Display omitted] •Primary amine citrate as amphiphilic molecules for SUPRAS phase formation.•Tetrabutylammonium bromide-induced coacervation in primary amine citrate system.•SUPRAS based on 1-octylamine citrate as efficient media for microextraction.•Microextraction of ochratoxin A from food samples followed by HPLC-FLD analysis.•Solidification of SUPRAS phase based on 1-octylamine citrate for extract collection