Green hydrophobic deep eutectic solvent-based rapid synergistic cloud point extraction and quantification of ultra-trace lead

• A rapid and eco-friendly HDES-RS-CPE–ETAAS method was developed for ultra-trace Pb. • L-menthol/1-octanol (1:1) DES efficiently extracted chelated Pb. • Extraction was completed in 2 min without heating or cooling, enabling high throughput. • Optimized parameters yielded high sensitivity. • Excellent recoveries were confirmed on real water samples. • The method complies with Green Analytical Chemistry principles for sustainability. In this study, a novel and environmentally friendly analytical procedure was developed for the fast separation and preconcentration of ultra-trace levels of lead from water samples at room temperature. The method is based on a hydrophobic deep eutectic solvent–assisted rapid synergistic cloud point extraction (HDES-RS-CPE), followed by electrothermal atomic absorption spectrometry (ETAAS) for quantification. The selected HDES was composed of L-menthol and 1-octanol in a 1:1 molar ratio, while ammonium pyrrolidine dithiocarbamate (APDC) and Triton X-114 were employed as the chelating agent and nonionic surfactant, respectively. Key experimental parameters influencing extraction efficiency were systematically investigated and optimized. Under optimal conditions, the method achieved a limit of detection (LOD) of 0.04 µg/L, a limit of quantification (LOQ) of 0.12 µg/L, and an enrichment factor (EF) of 38, with spike recoveries ranging from 94% to 104%. The method’s greenness, practicality and robustness were confirmed using various metrics demonstrated compliance with the principles of Green Analytical Chemistry, highlighting the method’s potential as a sustainable and efficient approach for ultra-trace lead quantification in environmental samples.