Molecularly imprinted polymer-based potentiometric sensor for 2-aminopyridine as a potential impurity in piroxicam

A molecularly imprinted polymer-based potentiometric sensor was fabricated for determination of 2-aminopyridine (2-AP). The electroactive component is the 2-APH(+) . To form this specie the determination is carried out in a bufferic solution at pH 4.5 in which 2-AP is prevalently monoprotonated. Under these conditions, the membrane potential, increases with 2-AP concentration over a wide range of concentration (5 µM to 100 mM) with a near Nernstian response of 54.1 mV/decade and detection limit of 2.0 µM. The response time is less than 5 s and the sensor can be used for more than 3 months without any significant divergence in response. The selectivity coefficients of the proposed sensor were evaluated and exhibited good selectivity to 2-AP with respect to the electrode based on a non-imprinted polymer. The utility of the sensor was successfully tested by examining of 2-AP in piroxicam (PX) as a potential impurity.