Development of molecularly imprinted polymer films used for detection of profenofos based on a quartz crystal microbalance sensor

Abstract

A quartz crystal microbalance (QCM) sensor based on molecularly imprinted ultra-thin films was developed for detecting profenofos in real samples. Films prepared by physical entrapment (MIP-A) and in situself-assembly (MIP-B) were compared. The results indicated that the best sensing signal was obtained through the in situself-assembly method. The QCM sensor chip was pretreated with 11-mercaptoundecanoic acid (MUA) to form a self-assembled monolayer (SAM), and then polymer films were immobilized directly on the SAM using surface-initiated radical polymerization. In this paper, all detection experiments were taken in air. The reaction was processed in solution, and the electrode was washed with deionized water and dried with N₂ before QCM measurement. The film was characterized by a scanning electron microscope (SEM), AC impedance and cyclic voltammetry. Analysis of the QCM response in the presence of different concentrations of profenofos showed a good linear correlation during 1.0 × 10⁻⁸ to 1.0 × 10⁻⁵ mg mL⁻¹ (y = 5log x + 42.5, R = 0.9960) and 1.0 × 10⁻⁵ to 1.0 × 10⁻³ mg mL⁻¹ (y = 25.86log x + 146, R = 0.9959), respectively. The MIP-QCM sensor was used to detect profenofos in tap water, and showed good recovery and repeatability.