Detection of Atrazine and its metabolites by photonic molecularly imprinted polymers in aqueous solutions

Abstract

Water contamination caused by atrazine (ATZ) application in agriculture is a risk to the environment and human health. Common analytical methods are expensive and complex. A sensor for low-cost and simple detection of ATZ and its metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), in aqueous solutions was developed by combining colloidal crystal with molecular imprinting technique. The sensor is formed by 3D interconnected macroporous structure with numerous nanocavities derived from ATZ and its metabolites imprinting in a thin polymeric film. Molecularly Imprinted Polymers (MIPs) were characterized by Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) and were incubated in solutions at variable concentrations. Target molecules were specifically absorbed in nanocavities and caused swelling in the polymer resulting in changes of Bragg diffraction peak wavelength. Kinetic tests showed that rebinding equilibrium was reached within 20 minutes. The sensor had a dynamic range of 0.1 to 10 ppb for quantifying target analytes in aqueous solutions with limit of detection of 0.1, 0.2, and 0.3 ppb, and limit of quantification of 0.33, 0.66, and 1 ppb for ATZ, DEA, and DIA, respectively. Cross-reactivity tests were conducted in 1 and 5 ppb solutions combining all three targets and showed absence of positive interference effects and low probability of false positives given by individual sensors. MIPs were examined in natural waters containing ATZ and its metabolites contamination, showing good agreement with real concentrations of targets. The MIP yields rapid and efficient detection of target molecules in aqueous solutions close to environmentally relevant concentrations.

Keywords

• Molecularly imprinted polymer
• chemosensor
• atrazine
• colloidal crystal
• Bragg diffraction