Nanomolar detection of p-nitrophenol via in situ generation of p-aminophenol at nanostructured microelectrodes

作者：Boateng Abraham; Brajter Toth Anna^*

来源：Analyst, 2012, 137(19): 4531-4538.

DOI：10.1039/c2an35811e

A new method and a new buffer medium, expected to be practical for miniaturized electrochemical immunoassays, were developed for rapid detection of nanomolar levels of p-nitrophenol (p-NP). The method exploits rapid reduction of p-NP to p-aminophenol (p-AP) by fast scan cyclic voltammetry at 500 V s(-1) at nanostructured carbon fiber microdisk electrodes (similar to 7 mu m dia.) fabricated from polyacrylonitrile (PAN) fibers. Large surfaces of the nanostructured microdisks facilitate the rapid reduction of p-NP to p-aminophenol (p-AP), as confirmed by the overlap with the analytical signals of the standards, which is then rapidly detected by fast scan cyclic voltammetry. A new 2-amino-2-(hydroxymethyl)propane-1,3-diol (Tris)-HAc buffer medium was developed in order to allow adaptation of this detection strategy to alkaline phosphatase (ALP)-based immunoassays. Tris-HAc is a stable medium, while the traditional Tris-HCl buffer medium produces large residual faradaic currents attributed to chloride oxidation. Addition of sodium acetate to a Tris-HAc buffer medium allows sensitivity enhancement by a factor of 2 to 0.85 nA mu M-1, similar to the best sensitivity reported at the nanostructured PAN carbon fiber microdisk sensors.

• 出版日期2012