Vortex-Assisted Liquid-Liquid Microextraction Combined with HPLC for the Simultaneous Determination of Five Phthalate Esters in Liquor Samples

A vortex-assisted liquid-liquid microextraction (VALLME) method using hexanoic acid as extractant followed by high-performance liquid chromatography-diode array detection was developed for the extraction and determination of five phthalate esters (PAEs) including bis-methylglycol ester (DMEP), benzyl butyl phthalate (BBP), dicyclohexyl phthalate (DCHP), di-n-butyl phthalate (DBP), and di-n-octyl phthalate (DNOP) from liquor samples. In this method, hexanoic acid was employed as extraction solvent, because its density is lower than water. And vortex mixing was utilized as a mild emulsification procedure to reduce emulsification time and improve the effect of extraction. Under the studied conditions, five phthalate esters were successfully separated within 20 min and the limits of detection were 2.3 ng mL(-1) for DMEP, 1.1 ng mL(-1) for BBP, 1.9 ng mL(-1) for DCHP, 1.2 ng mL(-1) for DBP, and 1.5 ng mL(-1) for DNOP, respectively. Recoveries of the PAEs spiked into liquor samples were ranged from 89 to 93 %. The precisions of the proposed method were varied from 1.6 to 2.6 % (RSD). The VALLME method has been proved to have the potential to be applied to the preconcentration of the target analytes. Moreover, the method is simple, high sensitivity, consumes much less solvent than traditional methods and environmental friendly.