A sensitive electrochemical sensor for rapid determination of methadone in biological fluids using carbon paste electrode modified with gold nanofilm

• Published in: Talanta (Oxford) 2014-10, Vol.128, p.203-210
• Main Authors: Afkhami, Abbas, Soltani-Felehgari, Farzaneh, Madrakian, Tayyebeh
• Format: Article
• Language: English
• Subjects: Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Carbon - chemistry; Electrochemical sensor; Electrochemical Techniques - instrumentation; Electrochemical Techniques - methods; Electrodes; Gold - chemistry; Gold nanoparticle; Human urine sample; Humans; Hydrogen-Ion Concentration; Metal Nanoparticles - chemistry; Methadone - analysis; Methadone - chemistry; Methadone - urine; Methadone determination; Reproducibility of Results; Saliva - chemistry; Square wave voltammetry
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2014.03.003

A novel and effective electrochemical sensor for the determination of methadone (MET) at pH 9.0 using gold nanoparticles, electrodeposited on a multi-walled carbon nanotube modified carbon paste electrode (GNPs/MWCPE), is introduced. The voltammetric behavior of MET at this modified electrode was studied using cyclic and square wave voltammetric techniques and the results were compared with those obtained at the multi-walled carbon nanotube modified carbon paste electrode (MWCPE). The oxidation of MET was irreversible and exhibited an adsorption controlled process at the GNPs/MWCPE and a diffusion controlled process at the MWCPE. The effect of various experimental parameters including pH, scan rate, and accumulation potential and time on the voltammetric response of MET was investigated. At the optimum conditions, the concentration of MET was determined using square wave voltammetry (SWV) in a linear range of 0.1–500.0µmolL−1 with a correlation coefficient of 0.9901 at the GNPs/MWCPE, and 0.5–300.0µmolL−1 with a correlation coefficient of 0.993 at the MWCPE and the detection limits were found to be 0.005 and 0.3µmolL−1, respectively. The proposed electrode was successfully applied to the determination of MET in a pharmaceutical dosage form, urine and saliva samples. The effects of common interferences, namely some of different cations and anions, on the current response of MET were investigated. This revealed that the GNPs/MWCPE shows excellent analytical performance for the determination of MET in terms of a very low detection limit, high sensitivity, very good repeatability and reproducibility. [Display omitted] •A new modified electrochemical sensor was constructed and used.•Gold nanoparticles and multiwalled carbon nanotubes were used as the modifiers.•The sensor was used for the determination of methadone in real samples.•Modification improved in the sensitivity and detection limit of the method.•The electrooxidation of methadone at the surface of the electrode was studied.