High selective colorimetric detection of Cd2+ ions using cysteamine functionalized gold nanoparticles with cross-linked DL-glyceraldehyde.

This paper reports an ingenious colorimetric sensor probe for the detection of Cd²⁺ ions using cysteamine functionalized gold nanoparticles cross-linked with DL-glyceraldehyde (DL-G-CA-Au NPs). Rapid aggregation in DL-G-CA-Au NPs was observed by adding Cd²⁺ ions at PBS buffer pH 7.0, which results in an immediate color change of the solution from red to blue. A red-shift in the wavelength of absorption peak was measured from 520 to 736 nm using UV-visible spectroscopy. The surface functionalization and aggregation of Au NPs were also characterized by recoding FI-IR and DSL data. The colorimetric probe was analyzed in the concentration of Cd²⁺ ions ranging from 0.05 to 500 μM, and a good linearity was observed towards the lower concentration levels with a coefficient of correlation <italic>R</italic>² = 0.9862. The limit of detection was found to be 21 nM, which best describes its superior performance over other reported colorimetric probes. Furthermore, the performance of the probe was not influenced by other metal ions, and the stability of DL-G-CA-Au NPs was maintained even after 30 days. The proposed method was successfully applied to various water samples collected from the environment, and an accuracy ≥ 98% was achieved. [ABSTRACT FROM AUTHOR]