Galvanostatic entrapment of penicillinase into polytyramine films and its utilization for the potentiometric determination of penicillin

A sensitive and reliable potentiometric biosensor for determination of penicillin has been developed by exploiting the self-limiting growth of the non-conducting polymer, polytyramine. Optimum polytyramine-penicillinase (PTy-PNCnase) films for potentiometric detection of penicillin were accomplished with monomer solutions which contained 0.03 M tyramine, 37 U/mL penicillinase, 0.01 M KNO3,and 3 mM penicillin with an applied current density of 0.8 mA/cm2 and an electropolymerisation time of 40 seconds. The potentiometric biosensor gave a linear concentration range of 3a??283 A?M for penicillin and achieved a minimum detectable concentration of 0.3 A?M. The biosensor was successfully utilized for the detection of Amoxycillin and gave an average percentage recovery of 102 A? 6 . Satisfactory recoveries of penicillin G were also achieved in milk samples with the potentiometric biosensor when concentrations are a?Y20 ppm.