Ultra-trace level detection of nickel(II) ions in real water samples using surface anchored recognition probes at liquid crystal sensing platform

Abstract

Rational fabrication approach for ultra-trace level detection of nickel (Ni(II)) ions in water samples has been developed using surface anchored recognition probes at liquid crystal sensing platform. In this system, the optimized volume per cent (5:1, %v/v) of synthesized surface anchored diacetate probes along with DMOAP decorated on glass substrate is able to perfectly align 5-cyanobiphenyl (5-CB) liquid crystal (LC) giving dark textural pattern. On the other hand, the fabricated probe is able to selectively reorient the transitions of the decorated LC molecules in the presence of Ni(II) ions too, leading to bright textural pattern under cross polarizers. The optimized and fabricated system demonstrated high selectivity and sensitivity, detecting Ni(II) ions as low as 0.08 μM (∼4.7 ppb) in distilled water and 0.8 μM (∼47 ppb) in real water with results observable to the naked eye. Moreover, the sensor can detect Ni(II) in drinking water, providing an approach to develop LC-based sensor for detection of natural water contaminants with simplified operating techniques.