Preparation a multi-walled carbon nanotubes-carbon paste electrode based on a sulfanyl phenyl Schiff’s base for selective determination of mercury(II) in environmental water samples

The electrochemical property of a recently synthesized ligand, 3-((3-mercaptophenyl) aminomethyl)benzene-1,2-diol has been investigated with the construction of a modified carbon paste electrode to find out of mercury ions in real samples. To modify the electrode, paraffin oil and multi-walled carbon nanotubes (MWCNT) were used as binder and modifier respectively. Under the optimized conditions, the electrode exhibits a Nernstian slope of 30.0±0.2 mV per decade for mercury(II) ions over a broad concentration range 1×10-7 to 1×10-1M with a R2 value of 0.996 at pH 4.5 in a 5 sec response time. The detection limit of the method for Hg2+ was 2.3×10−8 mol l−1. The influence of several potentially interfering ions such as K+, Ag+, Cd2+, Ni2+, Ca2+, Cr3+, Pb2+, Cu2+, Co2+, Mg2+, Fe2+, Al3+, La3+ and Fe3+ on the determination of Hg2+ was studied and no significant interference was observed. The proposed modified carbon paste electrode was successfully applied to the determination of mercury ions in real water samples.