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. Copyright © 2010 John Wiley & Sons, Ltd.