A highly selective colorimetric chemosensor for copper(II) based on N-phenyl-N’-(pyridin-2-yl)thiourea(HPyPT)

[Display omitted] •A highly selective colorimetric chemosensor for copper (II) is described.•The pyridyl-thiourea (NPPT) chemosensor was synthesized quantitatively using green chemistry technique.•The present chemosensor shows excellent sensitivity and selectivity for copper over a series of other metal ions under investigation.•The applications of the present protocol were extended for the determination of copper from alloys, synthetic mixtures and natural river water. An efficient synthesis and applications of a N-Phenyl-N’-(pyridin-2-yl)thiourea(HPyPT) as a chemosensor for the selective detection of Cu2+ over other common metal ion is described. The HPyPT chemosensor could detect Cu2+ by forming 1:1 complex in acidic media. The complex exhibits maximum absorption at 393nm with molar absorptivity 5.795×103lmol−1cm−1 and Sandell’s sensitivity was found to be 0.01096μgcm−2 of Cu2+; Beer’s law is obeyed in the range of 1μgcm−3–14μgcm−3. The standard deviation for ten replicate samples at 10μgcm−3 level of Cu2+ is found to be 0.08. The detection limit was found to be 0.065μgcm.−3 The yellowish green coloured complex of Cu2+ with HPyPT is stable up to 12h. Under optimized conditions, the HPyPT shows excellent sensitivity and selectivity for Cu2+ over a series of metal ions such as Fe2+, Fe3+, Al3+, Zn2+, Sn2+, Ni2+, Mn2+ Co2+, Cr+2, Cd+2, Hg2+, Au+3and Mg2+. The present chemosensor shows stable and consistent yellowish green coloration in acetic acid and there is no need to use buffer solutions for complexation. Moreover, the application of the present chemosensor was extended for the detection of Cu2+ from water, copper alloys such as brass and Monel metal.