A novel sugar pyrazolin-5-one based optical chemosensor for sequential detection of copper (II) and cyanide ions in real samples. Experimental and theoretical studies

•Novel colorimetric glyco-conjugated pyrazolone chemosensor for sequential chemosensing of Cu2+ and CN− in water was developed.•Sugar pyrazolone chemosensor revealed a high sensitivity and selectivity toward Cu2+ and CN− in water.•The LODs of Cu2+ and CN⁻ were calculated to be 0.27 and 1.07 μM.•Kit test based on silica matrix and unglycoconjugated derivative was prepared to detect Cu2+ and CN− in water. A novel colorimetric glyco-conjugated chemosensor for sequential detection of the copper (II) and cyanide ions in water has been developed starting from lactose pyrazolin-5-one derivative. The presented chemosensor revealed a high sensitivity and selectivity toward copper (II) and cyanide ions in water under competitive conditions in real samples. The calculated limit of detection for copper (II) and cyanide ions was 2.7 × 10−7 and 1.07 × 10−6 mol.L−1 respectively. Furthermore, the unglyco-conjugated chemosensor derivative was successfully utilized in the preparation of the kit test by its adsorption on the silica matrix surface for the detection of copper(II) and cyanide ions in aqueous water samples.