Rational designing of ZIF-67-derived CoO nanocomposite with hierarchical porous structure and extensive peroxidase mimetic activities for highly sensitive colorimetric detection of nitrite in drinking water.

A simple, fast, and cost-effective colorimetric nitrite (NO) sensor based on ZIF-67-derived CoO nanocomposite (ZCo-2 NC) structure has been developed. The prepared colorimetric sensor (ZCo-2 NC) was employed to sensitively detect NO in drinking water system by the exhibition of promising peroxidase-mimicking nanozyme-like features. The sensor manifest well-determined sensing response with excellent linear and wide range of NO sensitivity (0.001-0.810 μM). The lower detection-limit (LOD) and lower quantification-limit (LOQ) were 0.14 ± 0.05 nM and 0.72 ± 0.05 nM, respectively, which is far below the US-EPA limit (21.7 μM). Further, the sensor also provides strong selectivity response to NO, better reversibility (12 cycles), and commendable stability of 10 weeks. In addition, it also perceived astonishing practicality towards NO in real water samples. Thus, this study opens a new pathway for the sensitive detection of NO in drinking water for future endeavor.