Solid-phase extraction of estrogen hormones from water using multi-walled carbon nanotubes as sorbent

Abstract

Multi-walled carbon nanotubes were employed as a sorbent for solid-phase extraction of estrogen hormones (estrone, 17β-estradiol, and 17α-ethinylestradiol) from water solution. The solid-phase extraction (SPE) method was optimized by choosing an appropriate mass of the sorbent, volume, and initial pH of hormone water solution, as well as by choosing an appropriate organic solvent for extraction. Based on the obtained hormone recoveries, the following SPE conditions were chosen as optimal: 100 cm3 of hormone water solution at initial pH adjusted to 10; 20 mg of the sorbent; and methanol-dichloromethane mixture as elution solvent. Recoveries obtained under the optimal conditions ranged from 70.56 % for estrone, to 81.23 % for 17α-ethinylestradiol, with a relative standard deviation from 9.92 to 18.74 %