Based on the relative output current of the CelloZIFPaper electrode, there is high selectivity toward Pb 2+ compared to the other investigated metal ion species (Fig. ). Furthermore, there is a reduction peak at a potential of -0.47 V for Pb 2+ absent for other metal ions. These observations reveal that the CelloZIFPaper electrode can be used to detect Pb 2+ ions using electrochemicalbased sensing. Paper interaction with different concentrations of Pb 2+ was also recorded using LSV (Fig. ). CelloZIFPaper electrodes show a limit of detection (LOD) of 40 µM and 8 µM for membranes synthesized via ex-situ (Fig. ) and in-situ (Fig. ) procedures, respectively. . The use of CelloZIFPaper as a working electrode is cheaper than conventional electrodes such as glassy carbon electrodes (GCE) or gold (Au) electrodes (AE) for selective detection of Hg 2+ ions . CelloZIFPaper-based electrodes exhibit good current stability using the chronoamperometry test (Figure ). The presence of active sites such as nitrogen pyridinic-N and pyrrolic-N with two unpaired electrons acted as additional adsorption sites for metal ions . CelloZIFPaper can be used directly without carbonizing ZIF-8 to ZnO@C or deposition of other nanomaterials . It can be used directly without the need for binding or conductive materials. The electrode fabrication is simple and requires no tedious efforts . In addition, the presence of cellulose functional groups (-OH and -COOH) in CelloZIFPaper enhances the metal adsorption making it a good candidate for the electrochemical sensing of, for instance, Pb 2+ (Table ).