A piezoelectric immunosensor for the detection of cocaine

A piezoelectric crystal immunosensor has been developed for the detection and determination of cocaine in the concentration range 10-300 mu g/liter (part per billion) with a relative SD of 10-19%. Benzoylecgonine antibody, the major metabolite of cocaine, was layered onto the gold electrodes of a 10 MHz piezoelectric crystal, which was precoated with protein G. The protein G immobilization procedure showed the best results in terms of sensitivity, stability, and reproducibility. The piezoelectric immunosensor technology demonstrated in this work shows a successful application which could have a tremendous impact on drug of abuse monitoring. (C) 1996 Academic Press, Inc.