Highly sensitive detection of Cd(II) ions using ion-imprinted surface plasmon resonance sensors

Abstract

This study reports a sensitive sensor-based measurement technique for selective and sensitive detection of Cd(II) ions at low concentrations using ion-imprinted technology. Heavy metal pollution is an extremely hot topic on scientific research for several decades. Cd(II) is one of the most toxic and carcinogenic heavy metals. The limit of concentration of Cd(II) ions allowed to be found in the drinking water and industrial wastewater has been defined as 3 µg/L by the World Health Organization. Therefore, a simple, reliable and effective method is required for the determination of Cd(II) ions. Surface plasmon resonance sensor is the most commonly used optical sensors due to their unique ability for real-time monitoring the molecular binding events. We have proposed a sensitive experimental platform capable of achieving detection in 6–7 min. In this work, the benefits of three different approaches were compared according to their performance enhancement effects on sensors. Poly(hydroxyethyl methacrylate) thin-film, polymeric nanoparticles, and gold nanoparticles were separately used for designing sensors surface for the sensitive detection of Cd(II) ions. Combination of the signal enhancing properties of nanoparticles and ion-imprinting technique provided sensitive and selective detection with a comparatively low limit of detection value to the SPR sensor system. The limit of detection value has been defined as 0.01 µg/L for selective Cd(II) ions detection which is less than the value determined by the World Health Organization. The real time detection of Cd(II) ions from wastewater solutions (SPS Quality Control Material Waste Water Level 2) was also carried out by the SPR sensors.