Harnessing ternary quasi-hydrophobic natural deep eutectic solvents for in situ decomposition dispersive liquid-liquid microextraction: a sustainable analytical approach for triazole pesticides in aquatic environments.

Triazole fungicides (TFs) are difficult to determine in environmental water due to their high polarity, water solubility, and complex matrix interferences, while conventional extraction techniques are often plagued by low enrichment efficiency and high organic solvent consumption. To address these limitations, a novel effervescent-assisted dispersive liquid-liquid microextraction (EA-DLLME) strategy based on ternary quasi-hydrophobic natural deep eutectic solvents (NADESs) was developed. The NADESs, composed of terpenoids, long-chain alcohols, and short-chain carboxylic acids, were synthesized and combined with Na2CO3 to form an effervescent system. The hydrophilicity of the short-chain carboxylic acid enabled in situ decomposition, while the agitation effect of CO2 bubbles facilitated rapid extraction. FT-IR and 1H NMR characterized the solvent structure and dispersion mechanism. Under optimized conditions via response surface methodology and GC-MS analysis, the method exhibited a linear range of 0.5-1000 ng mL-1 (R2 > 0.99) for the three target TFs (myclobutanil, tebuconazole, and epoxiconazole), with limits of detection of 0.017-0.030 ng mL-1. The recoveries of spiked samples ranged from 89.17% to 111.2%, with relative standard deviations below 9.5%. Density functional theory calculations including electrostatic potential, Independent Gradient Model, and Reduced Density Gradient reveal that the NADES forms through electrostatic complementarity and a hydrogen-bond network, and that the extraction with TFs occurs via directional hydrogen bonding between triazole nitrogen and the hydroxyl group of thymol, with a binding energy of -23.66 kcal mol-1, further stabilized by van der Waals forces. This approach effectively overcomes the poor retention and low efficiency associated with traditional reversed-phase extraction, offering a simple, green, and practical tool for monitoring trace TFs in complex water samples.