**Abstract**

The present chapter emphases on the approach of electrochemical sensor of metallic oxide nanocomposites to sense/detect heavy metal ions. Several methods have been incorporated with modified electrode for the sensing/detection of heavy metal ions. Among these methods square wave anodic stripping voltammetry method and differential normal pulse voltammetry method have been tested and being recommended for the individual analysis as well as simultaneous analysis of heavy metal ions by various researchers. We also endorse the said methods as the best choice for sensing of heavy metal ions however the material phase (plane) is also of specific importance in this regard. We suggest that these methods may be practiced by chemical industries the main sources of heavy metal ions waste. Furthermore, the statistical approach for the detection limit (3σ method) has been illustrated in the last paragraph of this unit.

**Keywords:** electrochemical sensing, rGO/MOx, heavy metal ions, material phase (plane), statistical approach for the detection limit
