Colorimetric and voltammetric sensing of mercury ions using 2,2′-(ethane-1,2-diylbis((2-(azulen-2-ylamino)-2-oxoethyl)azanediyl))diacetic acid

Abstract

2,2′-(Ethane-1,2-diylbis((2-(azulen-2-ylamino)-2-oxoethyl)azanediyl))diacetic acid (L) derivative was used to develop novel multi-signal sensor platforms for mercury ions detection. Colorimetric and electrochemical sensors based on L were obtained and their ability to detect mercury ions from aqueous solutions was evaluated. Colorimetric detection has been achieved by paper-based colorimetry sensor or UV–Vis spectrometry. It based on the interaction between L (purple colour) and mercury ions leading to a yellow complex. The obtained colorimetric sensors have particular selectivity for Hg(II) ions against others metal ions. Chemically modified electrodes (CME) were obtained in a single step on glassy carbon disks by electrooxidation of L. These CMEs were used to detect mercury ions by anodic stripping method after pre-concentration through chemical interaction in open circuit. The electrode was selective and sensitive for these ions. After setting the optimal parameters of the sensors, the limits of detection were estimated to be 1.5 × 10−6 M, 7 × 10−8 M and 3 × 10−10 M by using PADs, UV–Vis spectrometry, and CME, respectively. The obtained sensors were successfully applied to detect Hg(II) ions content in natural water samples and the results were in agreement with those obtained by atomic spectrometry.