Selective picomolar detection of hexachlorobenzene in water using a quartz crystal microbalance coated with a molecularly imprinted polymer thin film

A molecular sensor for efficient and rapid recognition of hexachlorobenzene in water has been obtained by careful engineering of a thin, molecularly imprinted polymer thin film attached to a quartz crystal microbalance. Efficient imprinting was obtained in these films by controlling the heterogeneity of cross-linking in the polymer network and using appropriate electron-rich complements to the electron-deficient hexachlorobenzene. A comparison of the signals arising from two sensors, coated with imprinted and blank films respectively,unambiguously distinguishes hexachloroberizene from small molecules of similar sizes and structures (anisole, benzene, chlorobenzene, and cyclohexane). The investigated sensors demonstrate both high selectivity and sensitivity (down to 10(-12) mol L-1), while exhibiting an exceptionally fast response time (similar to10 s).