Extraction of neurotransmitters from rat brain using graphene as a solid-phase sorbent, and their fluorescent detection by HPLC

A simple, cost-effective and efficient method was developed for the determination of glycine, gamma-aminobutyrate and taurine in rat brain using graphene as a sorbent for solid-phase extraction. The analytes were eluted from a graphene-packed solid-phase extraction cartridge with methanol, derivatized at their amino groups with the fluorescent label 4-carboxy-2,6-dimethylquinoline N-hydroxysuccinimide ester, and then separated and fluorescently detected by HPLC. The type and volume of eluent, sample pH, extraction time and sample volume were optimized with respect to sensitivity and precision. Under optimal conditions, linear response is obtained in the concentration range from 0.1 to 50 mu g g-1, with correlation coefficients of > 0.990. The limits of detection are 23.4 ng g(-1) (gamma-aminobutyrate), 45.3 ng g(-1) (glycine) and 67.5 ng g(-1) (taurine) (S/N = 3). The results reveal the potential of graphene as a sorbent in the analysis of biological samples.