Microextraction of Tetracyclines from Milk to Deep Eutectic Solvents for the Subsequent Determination by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

• Published in: Journal of analytical chemistry (New York, N.Y.) Vol. 77; no. 3; pp. 334 - 341
• Main Authors: Cherkashina, K. D., Pochivalov, A. S., Shakirova, F. M., Shishov, A. Yu, Bulatov, A. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.03.2022; Springer; Springer Nature B.V
• Subjects: Analytical Chemistry; Antibiotics; Carboxylic acids; Chemistry; Chemistry and Materials Science; Fatty acids; High performance liquid chromatography; Mass spectrometry; Milk; Octanoic acid; Oxytetracycline; Solvents; Synergistic effect; Tetracyclines; Thymol; food products; high-performance liquid chromatography; deep eutectic solvents; tetracyclines; liquid–liquid microextraction
• ISSN: 1061-9348; 1608-3199
• DOI: 10.1134/S1061934822030042

A method of liquid–liquid microextraction is proposed for the extraction and preconcentration of tetracycline antibiotics from milk. It involves the extraction of analytes into a hydrophobic deep eutectic solvent ( DES ) based on a terpenoid and a carboxylic acid, followed by back extraction into the aqueous phase. A synergistic effect was revealed in the microextraction of tetracyclines into a DES phase based on thymol and octanoic acid (molar ratio of precursors 0.35 : 0.65), i.e., higher distribution ratios compared to those calculated using the additive scheme. Possibilities of the proposed method are shown on an example of the determination of tetracycline, chlortetracycline, and doxycycline in milk samples by HPLC–MS/MS. The limits of detection (3σ) for tetracycline and doxycycline are 5 ng/kg and for chlortetracycline,—50 ng/kg.