Surfactant-modulated ternary natural deep eutectic solvent-based hollow fiber liquid–liquid–liquid microextraction for the determination of bisphenols residues in waters

Herein, for the first time, a ternary natural deep eutectic solvent (NADES) was synthesized from nerol, menthol and formic acid, and was modulated by surfactant trioctylphosphine oxide (TOPO). A novel hollow fiber liquid–liquid–liquid microextraction method based on the NADES (SM-NADES-HF-LLLME) was proposed to enrich trace bisphenols (BPs) residues in water and subsequently detected by HPLC. The modulation of NADES with TOPO significantly improved the extraction efficiency (average enrichment factor) of BPs by 51.6 %. After performing single-factor optimization, a Plackett-Burman design was carried out to screen out four key factors, which were further optimized and evaluated by a central composite design. Under the optimal extraction conditions, the proposed method exhibited good linear relationship in the ranges of 0.36–400 μg L −1 ( r 2 ＞0.9994). The limits of detection (LODs) at three times ratio of signal to noise ( S/N = 3) and limits of quantification (LOQs, S/N = 10) for bisphenol A, bisphenol E, bisphenol F and bisphenol S were ranged from 0.11 to 0.49 and 0.36–1.62 μg L −1 , respectively. The intra-day and inter-day precisions ( n  = 6) were less than 4.1 % with enrichment factors ranged from 173 to 192. Bisphenol A with concentration of 4.42–13.71 µg/L was detected in real water samples with good recoveries (90.4–105.6 %). The proposed SM-NADES-HF-LLLME/HPLC method proved to be a green alternative for the determination of bisphenoic compounds in environmental waters.