A Green, Rapid and Efficient Dual-Sensors for Highly Selective and Sensitive Detection of Cation (Hg(2+)) and Anion (S(2−)) Ions Based on CMS/AgNPs Composites

Detection of mercury (Hg(2+)) and sulfide (S(2−)), universal and well-known toxic ions, is crucial in monitoring several diseases. How to design and fabricate the high-performance sensor for simultaneously and accurately detecting the Hg(2+) and S(2−) is critical. Herein, we proposed a novel and convenient strategy for optical detection of Hg(2+) and S(2−) by employing a carboxymethyl cellulose sodium/silver nanoparticle (CMS/AgNPs) colloidal solution, in which AgNPs were used as monitor for Hg(2+) and S(2−), and the CMS was utilized as both the stabilizer and the hydrophilic substrate for AgNPs. Well-identifiable peaks for Hg(2+) and S(2–) were obtained in water based on UV–VIS absorption spectra, the absorbance intensity and/or position of nano-silver vary with the addition of Hg(2+) cation and S(2–) anion, accompanying with color change. Impressively, the optimal AgNPs anchored CMS exhibited a high sensitivity and selectivity toward Hg(2+) and S(2−), the change in absorbance was linear with the concentration of Hg(2+) (0–50 μM) and S(2−) (15–70 μM), and the lowest limits of detection (LOD) were 1.8 × 10(−8) M and 2.4 × 10(−7) M, respectively. More importantly, owing to the superior properties in testing Hg(2+) and S(2−), the fabricated sensor was successfully applied for detection of target ions in lake and tap water samples. All these good results implied that the designed strategy and as-designed samples is promising in detecting cation (Hg(2+)) and anion (S(2−)) ions and open up new opportunities for selecting other kinds of ions.