An electrochemical sensor for sodium dodecyl sulfate detection based on anion exchange using eosin Y/polyethyleneimine modified electrode

A simple and effective method for the detection of electrochemically inactive sodium dodecyl sulfate (SDS) has been designed, based on different binding affinity of polyethyleneimine (PEI) toward electrochemically active eosin Y and electrochemically inactive SDS. The stronger binding affinity of the PEI toward SDS than eosin Y results in the decrease of the redox peak current of surface confined eosin Y and provides a quantitative readout for the SDS. The difference in value of the cathodic peak current showed a linear relationship with SDS concentration in a concentration range from 1 to 40 μg mL⁻¹, and a detection limit of 0.9 μg mL⁻¹ for SDS was obtained. Furthermore, the method has been successfully applied to the detection of SDS in real samples. The developed approach provided a simple and reliable detection for SDS and might have potential applications in electrochemical methods for inactive molecules.