Determination of phenolic compounds in water samples by HPLC following ionic liquid dispersive liquid-liquid microextraction and cold-induced aggregation

We report on the determination of bisphenol A and 2-naphthol in water samples using ionic liquid cold-induced aggregation dispersive liquid-liquid microextraction combined with HPLC. Parameters governing the extraction efficiency (disperser solvent, volume of extraction and disperser solvent, pH, temperature, extraction time) were optimized and resulted in enrichment factors of 112 for bisphenol A and of 186 for 2-naphthol. The calibration curve was linear with correlation coefficients of 0.9995 and 0.9998, respectively, in the concentration range from 1.5 to 200 ng mL −1 . The relative standard deviations are 2.3% and 4.1% (for n  = 5), the limits of detection are 0.58 and 0.86 ng mL −1 , and relative recoveries in tap, lake and river water samples range between 100.1 and 108.1%, 99.4 and 106.2%, and 97.1 and 103.8%, respectively. IL-CIA-DLLME has a high enrichment factor (112, 186), acceptable relative recovery (97.1%–108.1%), good repeatability (2.3%, 4.1%) and a wide linear range(1.5–200 ng mL −1 ) for the determination of bisphenol A and 2-naphthol.