Direct electrochemical detection of 4-aminophenol in pharmaceuticals using ITO electrodes modified with vertically-ordered mesoporous silica-nanochannel films

4-Aminophenol (4-AP) served as the drug intermediates has been widely used or found in pharmaceutical preparations. Therefore, direct and rapid determination of 4-AP content in pharmaceuticals is highly important for human health. In this work, we demonstrate a simple and fast electrochemical method for direct analysis of 4-AP in pharmaceuticals by using the indium tin oxide (ITO) electrode modified with vertically-ordered mesoporous silica-nanochannel films (VMSF). Arising from the vertically-aligned nanochannels and high porosity of VMSF, 4-AP could permeate the VMSF and transfer to the underlying electrode surface, ultimately giving rise to the electrochemical signal. By using the differential pulse voltammetry (DPV) method, the VMSF/ITO sensor was able to detect 4-AP in a wide linear range from 0.5 μM to 400 μM. The obtained limit of detection was calculated as 0.32 μM. Owing to the good anti-fouling and anti-interference ability of VMSF, direct analysis of 4-AP in pharmaceuticals was achieved, without any complex sample pretreatments.