Naked eye sensor on polyvinyl chloride platform of chromo-ionophore molecular assemblies: A smart way for the colorimetric sensing of toxic metal ions

We demonstrate the possibility of fabricating a simple, naked eye colorimetric sensor miniature, using chromo-ionophore molecular assemblies anchored on polyvinyl chloride (PVC) surface. The ion-sensing probe (4- n-dodecyl-6-(2-thiazolylazo)-resorcinol) provides a better efficiency with PVC platform in developing a series of colour transitions, while targeting trace levels of Cd 2+, Pb 2+ and Hg 2+. The physical properties of the film sensor are controlled by measuring the probe isotherm plot. The surface morphology and molecular composition of the solid-state optical sensor are characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The changes in sensor's optical intensity and its response time for the target analytes are followed by absorption spectroscopy. High speed of response ( t ≤ 5 min) and confidence in determination of analytes from chemically complex matrices has been achieved, using simulated synthetic mixtures and spiked real environmental samples, with a relative standard deviation of