Electrochemical preparation of two nanostructured poly(sulfosalicylic acid) films with different morphologies and properties for selective sensing of dopamine: Comparative study

- Two nanostructured poly(sulfosalicylic acid) (PSA) films were synthesized via potentiodynamic electropolymerization.
- PSA film synthesized from aqueous solution is smoother with better permselectivity.
- PSA film synthesized from aqueous solution shows better discrimination and lower detection limit for dopamine.
- PSA film synthesized from ionic liquid shows better reproducibility and stability for dopamine detection.

Two nanostructured poly(sulfosalicylic acid) (PSA) films were synthesized from room temperature ionic liquid (RTIL) or aqueous solution on a glassy carbon electrode (GCE) via potentiodynamic electropolymerization. The morphology and properties of the PSA films were characterized with scanning electron microscopy (SEM), scanning probe microscopy (SPM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). It was found that solvent had a major influence on the morphology and electrochemical properties of the resultant PSA films. The PSA(Ι) film, which was prepared from RTIL, consists of granular particles with cracks, whereas the PSA(II) film prepared from aqueous solution consists of nano-triangles with a more compact surface. The blocking effect of the PSA(Ι) film for the [Fe(CN)6]3 −/4 − electrochemical probe is much stronger, and a remarkably enhanced voltammetric response of the [Ru(NH3)6]3 + electrochemical probe can be observed for the PSA(II) film. When it is used to detect dopamine in the presence of a high concentration of ascorbic acid, PSA(II)/GCE has three linear parts with better discrimination and a detection limit of 0.03 μM. For PSA(Ι)/GCE, there are two linear parts with a detection limit of 0.05 μM. However, the reproducibility and storage stability of PSA(Ι)/GCE are better than those of PSA(ΙI)/GCE.

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