On the thermal and chemical stability of molecularly imprinted polymers

The thermal and chemical stability of a theophylline imprinted methacrylic acid¯ethylene glycol dimethacrylate co-polymer has been investigated. Radioligand binding studies have been used to study the changes in theophylline recognition characteristics of this and a non-imprinted, reference polymer arising from exposure to elevated temperatures and a range of chemical environments. Polymers were shown to withstand exposure to temperatures of up to 150°C (for 24 h) without loss of affinity for the template. Temperatures above this point induced a rapid loss in binding capacity and a concomitant mass loss. FT-IR indicated that this arises from decarboxylation of the polymer. The polymers exhibited remarkable resistance to extremes of pH, organic base and to autoclave treatment. This study provides an indication as to the limits of polymer stability, which is of significance for the practical use of this type of polymer, e.g. in sensor-based applications.