Molecular complex based dispersive liquid–liquid microextraction for simultaneous HPLC determination of eight phenolic compounds in water samples

A method for the simultaneous determination of eight phenolic compounds (PCs) with a wide polarity range in water samples has been developed and validated using molecular complex based dispersive liquid–liquid microextraction (MC-DLLME) followed by high-performance liquid chromatography. In this process, the molecular complex acted as the extractant, which was formed by tributyl phosphate (TBP) and 1-octanol through hydrogen bond interaction in situ, using a disposable polyethylene pipette for the extraction. The extraction mechanism was investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), which demonstrated that a TBP-1-octanol complex formed via P O HO hydrogen bonding . Furthermore, the extraction mechanism in the dual extraction solvent system involves hydrogen bonding for polar PCs and physical extraction for weak polar and apolar ones. Under the optimum conditions, detection limits were in the range 0.4–5.51 ng/mL and recoveries for the real samples varied from 82.0% to 104.7%, with a relative standard deviation (RSD) of <9.1%. The developed method is simple, inexpensive and sensitive and was successfully applied to the extraction and determination of phenolic compounds in water samples.