Cetyltrimethylammonium micelles enhance the sensitivity of ssDNA-based electrochemical sensor for the determination of pyridoxol

Abstract

A micellar interface composed of ssDNA and cetyltrimethylammonium bromide (CTAB) on the surface of a glassy carbon electrode is successfully fabricated by self-assembly. The as-fabricated micellar interface dramatically enhances the sensitivity to pyridoxol. The sensitivity is increased by two orders of magnitude, compared to that without CTAB. The voltammetric measurements show that the height of peaks is proportional directly to the concentration of pyridoxol in the range of 5.0 × 10⁻⁶ mol L⁻¹ to 6.5 × 10⁻⁴ mol L⁻¹. The linear regression equation obtained is I_p (μA) = 0.04043c (μmol L⁻¹) + 1.04633 with R = 0.9985 (n = 8) and SD = 0.5771. The detection limit is estimated at 1.2 × 10⁻⁶ (±0.1) mol L⁻¹ (S/N = 3). The measurements for real samples show good consistency to that measured by ultraviolet spectroscopy. The enhancing effect of CTAB is attributed to forming bilayer aggregates of cetyltrimethylammonium on the ssDNA film electrode.