Abstract
This work describes the design and integration of single-walled carbon nanotube-poly (amino benzene sulfonic acid) on gold electrode using Self-assembled monolayers (SAMS) technique. The integrated nanostructured films were confirmed using atomic force microscopy and field emission scanning electron microscopy. Further studies using voltammetry and impedance revealed the stability of the diffusion controlled reactions occurring on the integrated films on the electrode surface.
The Au-DMAET-(SWCNT-PABS) electrode was found to have a greater electron transfer as compared to the bare Au and Au-DMAET electrode. All the SAMS on the electrode surface gave a pseudo capacitance behaviour on impedance spectroscopy.
Au-DMAET-(SWCNT-PABS) electrode was able to detect Hg(II) and Cr(VI) in aqueous media under optimum conditions of 0.1 M HCl at pH 3, deposition time of 90 s and deposition potential of -0.1 V. Under these conditions, the sensor electrode achieved a detection limit of 0.06 μM with linearity between 20 nM and 250 nM was achieved for Hg(II). Cr(VI) stripping peak was found to be best prominent in 0.1 M KOH at pH 13 with deposition time of 30 s and deposition potential of -0.2 V. Under these conditions, the sensor electrode achieved a detection limit of 0.08 μM with linearity between 5 ppb and 50 ppb. For both analytes, the sensor electrode was found to be prone to interferences when tested against common heavy metals at two fold concentrations higher than that of the analytes.
The method developed for each analyte together with the sensor electrode was able to detect comparable concentrations of mercury and chromium in two water samples with ICP-OES as a reference method. The t-test results of the two methods revealed random errors as associated to the results...
M.Sc. (Nanoscience)