Determination of trace palladium by differential pulse stripping voltammetry using a chitosan-multi-wall carbon nanotubes modified glassy carbon electrode
QI Lei, QI Tong-xi
School of Chemistry and Chemical Engineering, Nanjing University
Abstract：Multi-wall carbon nanotubes (MWCNT) were dispersed in chitosan (CTS) solution, and the mixture obtained was used in modifying the surface of glassy carbon electrode (GCE) to prepare chitosan-multi-wall carbon nanotubes modified glass carbon electrode (CTS-MWCNT-GC). The stripping voltammetric characteristics of palladium at this electrode were studied with differential pulse stripping voltammetry. A new method for the determination of trace palladium was described after the determination conditions were optimized. It was found that palladium could be enriched on the surface of this modified electrode at -400 mV in 0.1 mol/L sodium acetate -0.1 mol/L hydrochloric acid buffer solution (pH 4.10). When scanning from -300 mV to 400 mV at the rate of 100 mV/s, , a sensitive differential pulse stripping peak appeared at 135 mV (vs. SCE) for palladium. The peak current showed good linearity with the concentration of palladium in the range of 1.88×10-9-1.69×10-8 mol/L. Detection limit was 3.10×10-10 mol/L. The modified electrode showed good stability and reproducibility. The relative standard deviation (RSD) was 0.21 % for 11 continuous determinations of 1.0×10-9 mol/L Pd solution. This method has been applied to the determination of trace palladium in ore samples, and the results were consistent with those obtained by FAAS.
