Disposable electrochemical immunosensor array for the multiplexed detection of the drug metabolites morphine, tetrahydrocannabinol and benzoylecgonine.
Heroin, marijuana and cocaine are widely abused drugs. Their use can be readily detected by analyzing urine for the metabolites morphine (MOR), tetrahydrocannabinol (THC) or benzoylecgonine (BZC). A multiplex immunosensor is described here for detection of MOR, THC and BZC using screen printed carbon array electrodes modified with gold nanoparticles. Antibodies against MOR, THC and BZC were immobilized on eight electrodes in a sensor array simultaneously, and a competitive assay was used for the detection. The free analytes in the sample compete with bovine serum albumin-conjugated analytes for the immobilized antibodies on the sensor surface. The array is capable of detecting the three drugs simultaneously within 20-40 min. The method has a high sensitivity, with detection limits as low as 1.2, 7.0, and 8.0 pg.mL