Conjugated Polyelectrolyte/Graphene Multilayer Films for Simultaneous Electrochemical Sensing of Three Monohydroxylated Polycyclic Aromatic Hydrocarbons

Monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) are polycyclic aromatic hydrocarbon (PAH) metabolites that have been used widely as biomarkers for evaluating human PAH exposure. In this paper, we present the design and synthesis of a water-soluble conjugated polyelectrolyte (PBCSO3Na) for use in a PBCSO3Na/graphene multilayer electrochemical sensor prepared using a layer-by-layer self-assembly method for the simultaneous detection of three OH-PAHs (namely, 2-hydroxynaphthalene, 3-hydroxyphenanthrene, and 1-hydroxypyrene). The homogeneous and controllable PBCSO3Na and graphene multilayer films formed via π–π interactions not only disperse well in water owing to the ionic side chains of PBCSO3Na but also prevent the aggregation of graphene by electrostatic repulsion. The developed sensor exhibits high electrocatalytic activities for the target OH-PAHs, and the electrochemical responses obtained under the optimal experimental parameters for the detection of 2-hydroxynaphthalene, 3-hydroxyphenanthrene, and 1-hydroxypyrene are found to be linear in the concentration ranges of 10–140, 10–160, and 20–130 nM with detection limits of 1.43, 2.31, and 10.42 nM for a signal-to-noise ratio of 3, respectively. The practical analytical applicability of the proposed sensor is verified by its application to spiked human urine samples, and the results demonstrate appropriate anti-interference capabilities and excellent recoveries in the range of 99.0–106.0%.