Electrochemical determination of theophylline on a glassy carbon electrode modified with reduced graphene oxide-sodium d
- PDF / 861,560 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 88 Downloads / 303 Views
2107
Electrochemical determination of theophylline on a glassy carbon electrode modified with reduced graphene oxide—sodium dodecyl sulfate—Nafion composite film M. Hamidi and K. Zarei School of Chemistry, Damghan University, Damghan, Iran. E-mail: [email protected] An electrochemical sensor based on glassy carbon electrode modified with reduced graphene oxide—sodium dodecyl sulfate—Nafion* composite film was constructed and used to determine theophylline. The synthesized graphene oxide and surface morphology of the reduced graphene oxide—sodium dodecyl sulfate—Nafion film were characterized using IR spectroscopy, X-ray diffraction studies, and electrochemical impedance spectroscopy. The electrochemical behavior of the theophylline on the modified electrode was investigated using cyclic voltammetry and adsorptive differential pulse voltammetry. Under optimized analytical conditions, the electrode showed a linear response at concentrations of theophylline of 0.01—0.10, 0.1—1.0, and 1.0—40 mol L –1 with the detection limit of 5 nmol L –1. Key words: theophylline, reduced graphene oxide, sodium dodecyl sulfate, Nafion, electrochemical sensors.
Theophylline (TP, 1,3-dimethyl-7H-purine-2,6-dione, 1) can be found in pharmaceutical formulations and foodstuffs. It is also used as bronchodilator and respiratory stimulant for the treatment of asthma and lung diseases.1 However, high doses of TP may lead to insomnia, anorexia, and heartburn tachycardia.2 Therefore, there is a need for development of a low-cost, simple, sensitive and rapid method for determination of TP in pharmaceutical and foodstuff samples. Some methods have been reported for determination of TP, such as spectrophotometry,3 gas and liquid chromatography-mass spectrometry, 4,5 molecularly imprinted solid phase extraction, 6 high performance liquid chromatography,7 and electrochemical methods.1,8—14. In comparison to the other options, electroanalytical methods have the advantages of simplicity, fast results, and high sensitivity. Characteristics of some known electroanalytical sensors for the TP determination and developed herein an electrochemical sensor based on glassy carbon electrode (GCE) modified with reduced graphene oxide—sodium dodecyl sulfate—Nafion* composite film are summarized in Table 1.
* Nafion is a sulfonated tetrafluoroethylene-based fluoropolymer.
Reduced graphene oxide (RGO) is one of the most important derivatives of graphene, which has a large surface area, low cost, strong mechanical strength, and excellent conductivity. Therefore, it can be used for developing novel electronic devices, such as chemical sensors and biosensors. Graphene oxide- (GO) and RGO-based electrochemical sensors have been developed for the sensitive determination of ascorbic acid, dopamine, and uric acid15 and pyridoxine.16 Surface active agents (surfactants) are amphiphilic molecules with a polar head at one end and a long hydrophobic tail at another. Surfactants are often applied in electroanalytical chemistry to enhance and alter the properties of the electrode/solution inter
Data Loading...
