In this work, the development of a novel enantioselective sensor is described using chiral imprinted nanoparticles as recognition elements. Imprinted nanoparticles, synthesised via precipitation polymerisation, were incorporated in a polyvinyl chloride membrane which served as the sensing element to construct a potentiometric sensor selective to the S enantiomer of the antidepressant drug citalopram (SCIT). The effect of the amount of nanoparticles, the type and quantity of plasticiser and the concentration of the internal reference solution were assessed in order to have a sensor with best sensor performance. The fabricated sensor showed Nernstian behaviour with a slope of 50.77 +/- 1.32 mV decade (1) in SCIT+ solutions that ranged from 2.5 x 10 (7) to 10 (3) mol L (1). Sensor applicability to urine samples was also tested using spiked urine samples as quality control samples as well as urine collected from a volunteer who had been treated with this drug. The fabricated sensor was capable of accurately determining SCIT+ with good precision (RSD 2.07-6.56%) at different concentration levels. (C) 2016 Elsevier Ltd. All rights reserved.