Selective extraction of light polycyclic aromatic hydrocarbons in environmental water samples with pseudo-template thin-film molecularly imprinted polymers

Abstract

An interesting approach to environmental analysis of trace level contaminants in the environment is molecular imprinting. This article describes the fast, low-tech preparation and evaluation of thin-film molecularly imprinted polymers (MIPs) for the specific uptake of light polycyclic aromatic hydrocarbons (PAHs) from complex aqueous matrices. Detection is carried out using offline gas-chromatography-mass spectrometry (GC-MS). The use of toluene as a pseudo-template eliminates the problem of positive errors associated with incomplete template removal when the template and analyte are identical. These MIPs give a linear response in standard aqueous solutions and spiked wastewater over a concentration range of 10 to at least 100 μg L⁻¹, and superior selectivity over the non-imprinted materials. In MIP uptake studies for PAHs at environmentally relevant concentrations in spiked seawater samples, linearity was obtained over the range studied (0.5–5 μg L⁻¹) with R² values from 0.978 (naphthalene) to 0.997 (pyrene). Other than addition of standards for calibration, all environmental samples were used unmodified. Good recoveries owing to good selectivity, good response linearity and a good uptake trend overtime indicate these materials are suitable for in situ monitoring or remote monitoring.