An ultrasensitive electrochemiluminescence sensor for detecting diphenhydramine hydrochloride based on l-cysteine-functionalized multiwalled carbon nanotubes/gold nanoparticles nanocomposites

A new electrochemiluminescence (ECL) sensor was constructed for the ultrasensitive detection of diphenhydramine hydrochloride (DPH) based on l -cysteine-functionalized multiwalled carbon nanotubes/gold nanoparticles (MWCNTs-Cys-AuNPs) nanocomposites. In this work, the nanocomposites were facilely synthesized by using l -cysteine as linking agent which could covalently conjugate to MWCNTs and AuNPs via amide bond and Au S bond. Herein, the prepared MWCNTs-Cys-AuNPs were used as matrix material and fixed by Nafion to adsorb Ru(bpy) 3 2+ on glassy carbon electrode (GCE) to provide a new ECL sensor for DPH . Then the electrochemical and ECL behaviors of the sensor were investigated. Approximate 9-fold enhancement in ECL intensity was observed after addition of DPH. By optimizing the experimental conditions, the proposed ECL sensor exhibited excellent assay performances in determination of DPH with a wide linear range (2   ×   10 −8 –7.5   ×   10 −4   M), low detection limit (6.7   ×   10 −9   M), good reproducibility and acceptable stability. Furthermore, the constructed ECL sensor was used to analyze the DPH in real sample with a satisfactory result, which holds a great potential in the field of pharmaceutical analysis.