Simple and solvent-free synthesis of Zeolitic Tetrazole Framework based MOF for selective and sensitive electroanalysis of silver ions in drinking water

Human silver poisoning through water consumption constitutes a real public health concern nowadays. Thus, the development of sensitive, accurate and low-cost tools for silver ions (Ag+) determination in drinking water would significantly help in facing this great challenge. Herein, a cost effective and eco-friendly material namely Zeolitic Tetrazole Framework (ZTF-8) was synthesized and used as electrode material for Ag+ ions electroanalysis. XRD, FT-IR, TGA, XPS and FE-SEM were utilized to evidence the successful synthesis of the electrode material. Electrochemical characterization of the associated sensor revealed its good affinity towards Ag+ ions as well as the satisfactory repeatability and reproducibility of the obtained results. The sensor optimization showed that to achieve its best performance, 3 mu L of ZTF-8 suspension, 1 mg/mL should be utilized for its fabrication. Given that the sensing mechanism was based on the deposition of Ag0 on the sensor surface followed by their redissolution, the sensor optimization also revealed that the optimal deposition potential and time are -0.1 V vs. SCE and 200 s, respectively. Calibrated in concentration range of 0.2 to 1.6 mu M, the prepared sensor exhibited a linear relationship (0.997) with a sensitivity of (0.56 +/- 0.01) mu A/mu M; the statistic limit of detection was found to be 0.9 nM. Moreover, the fabricated sensor showed great potential for real samples analysis and satisfactory recoveries in mineral water, tap water, water obtained from a reverse osmosis plant and in an AAS standard solution. Furthermore, obtained results were validated using FAAS and ICP-OES.