Voltammetric detection of 4-chlorophenol using a hybrid composite based on graphene oxide and dendrimeric complex

This work reports the synthesis and characterization of a novel hybrid composite based on graphene oxide (GO) functionalized with a first-generation polyamidoamine dendrimer (PAMAM G1), further complexed with zinc and potassium hexacyanoferrate(III). The objective was to develop a chemically stable and sensitive electrochemical platform for the voltammetric detection of 4-chlorophenol (4-CP). The materials were synthesized and characterized using FTIR, XRD, XPS, SEM, TEM, and EDX techniques. The electrochemical behavior of the resulting composite (OGDZnH) was investigated by cyclic voltammetry. The modified electrode demonstrated a well-defined redox couple attributed to the Fe(II)/Fe(III) transition mediated by the Zn complex. Under optimized conditions (pH 7.0, 1.0 mol L−1 KCl, scan rate of 20 mV s−1), the electrode showed high sensitivity for 4-CP with two linear ranges: from 1.0 × 10−6 to 9.0 × 10−6 mol L−1 and from 1.0 × 10−5 to 1.0 × 10−4 mol L−1, and detection limits as low as 2.69 × 10−7 mol L−1. Interference studies confirmed good selectivity in the presence of common ions, and recovery tests in river water samples yielded satisfactory results. These findings suggest that the OGDZnH-modified electrode is a promising and low-cost platform for environmental monitoring of 4-chlorophenol.