Phytic acid induced three-dimensional graphene for the enrichment of phthalate esters from bottled water and sports beverage samples.

A three-dimensional graphene was synthesized through a hydrothermal reaction of graphene oxide with phytic acid. The microstructure and morphology of the phytic acid induced three-dimensional graphene were investigated by nitrogen adsorption-desorption isotherms, scanning electron microscopy, and transmission electron microscopy. With a large surface area and three-dimensional structure, the graphene was used as the solid-phase extraction adsorbent for the extraction of phthalate esters from bottled water and sports beverage samples before high-performance liquid chromatographic analysis. The results indicated that the graphene was efficient for the solid-phase extraction of phthalate esters. The limits of detection (S/N = 3) of the method for the analytes were 0.02-0.03 ng/mL for the water samples and 0.03-0.15 ng/mL for the sports beverage sample. The limits of quantitation (S/N = 9) for the analytes were 0.06-0.09 ng/mL for water samples and 0.09-0.45 ng/mL for sports beverage sample. The calibration curves for the phthalate esters by the method had a good linearity from 0.1 to 80.0 ng/mL with correlation coefficients larger than 0.9997. The recoveries of the analytes for the method fell in the range of 86.7-116.2% with the relative standard deviations between 1.5 and 6.8%.