An ultrasensitive electrochemical sensor based on nanoporous molecularly imprinted polymer film for triphenyl phosphate detection

As a representative of widely used flame retardant, triphenyl phosphate (TPhP) has been regarded as an emerging environmental contaminant of health concern. In this study, an ultrasensitive disposable screen-printed electrode (SPE) electrochemical sensor has been developed based on covering the electrode with a nanoporous molecularly imprinted polymer (NPMIP) film for detecting TPhP. The mechanism of the sensor was revealed by analyzing the electrokinetic motion of the redox probe inside the nanochannel of the NPMIP film. Following optimization, the sensor was found to be rapid with the detection time of approximately 35 min, showing a linear relationship to the logarithmic concentration of TPhP between 1 fM and 1 µM (R² = 0.99) and low limits of detection and quantification (LOD = 0.3 fM, LOQ = 0.9 fM). Moreover, the sensor presented more than four times better recognition of TPhP than its non-imprinted recognition. In addition, an excellent adaptability of the sensor in analyzing real samples was indicated, with recovery of 100–106 % for lake water and 92–109 % for sea water. The presented analytical approach possesses the advantages of high sensitivity, easy fabrication and low cost, which could be further developed as a portable device for onsite environmental monitoring.