Voltammetric analysis of diphenhydramine in pharmaceutical samples using a nanostructure based sensor

Diphenhydramine which is a first generation antihistamine has been mainly used for the treatment of allergies and itchiness, insomnia, motion sickness, and extrapyramidal symptoms.Additionally, Diphenhydramine has significant antitussive activity [1]. Therefore, determination of diphenhydramine is very important in pharmaceutical and biological samples. A new room temperature ionic liquid modified CdO/SWCNTs carbon paste electrode had beenfabricated by using hydrophilic ionic liquid 1-methyl-3-butylimidazolium chloride as a binder. In the first step, we synthesized CdO/SWCNTs using direct chemical precipitation methods and nanocomposite characterized with TEM method. Figure 1 shows a typical TEM for synthesizednanocomposite. The cyclic voltammogram showed an irreversible oxidation peak signal for diphenhydramine at a surface of modified electrode. Compared to bare carbon paste electrode, the electrochemical response was greatly improved for diphenhydramine electrooxidation. Detection limit ofmorphine was found to be 0.03 μM using square wave voltammetry (SWV) method. The proposed sensor was successfully applied for the determination of diphenhydramine in human urine and pharmaceutical samples.

Keywords:

Diphenhydramine , CdO/SWCNTs nanocomposite , Ionic liquids , Voltammetric analysis