Ferrocene-terminated dendrimer functionalized graphene oxide layered sensor toward highly sensitive evaluation of Di(2-ethylhexyl) phthalate in liquor samples.

We demonstrate the use of a dendrimer functionalized graphene oxide (GO) to fabricate a novel sensitive ferrocene-terminated poly(amine) ester dendrimer (Fc-AED)-GO modified glassy carbon electrodes (Fc-AED/GO/GCE) for direct quantification of Di(2-ethylhexyl) phthalate (DEHP) in liquor sample. GO sheets were grafted on the Fc-AED molecules by the esterification reaction between carboxylic end group in Fc-AED and hydroxyl group on GO sheets so as to form Fc-AED-GO composites. Construction of electrochemical sensors using the structure of nanosized dendrimer can provide compact matrix for the incorporation of GO to improve the adhesion of GO on electrode, which would be more possible for the design of sensor to improve the film forming performance and then increase the electrochemical activity of the electrode. Additionally, it can directly use the redox probe of ferrcene to sense the content variation of analyte. The GO also provides a larger surface area to facilitate deposition of Fc-AED redox probe resulting in the increased current response of the modified sensor. The modified sensor exhibites a wide linear response to DEHP and a low detection limit of 0.06 µM with higher sensitivity, good selectivity, and a better reproducibility promising to be a useful tool in the DEHP evaluation. The outstanding performance of the developed sensor could be attributed to the synergistic effect of Fc-AED and GO. Possible redox mechanism of DEHP on Fc-AED/GO/GCE are proposed based on experimental results.