Electrochemical Behavior and Voltammetric Determination of Theophylline at a Glassy Carbon Electrode Modified with Graphene/Nafion

Abstract

An ultrasensitive voltammetric sensor, a simply coated graphene-Nafion suspension on a glass carbon electrode surface, was fabricated and used to investigate the electrochemical behavior of theophylline as described in the present paper. The results indicated that this voltammetric sensor exhibited a special recognition capacity to determine theophylline as well as having high sensitivity due to the excellent characteristics of graphene and the adsorption action of Nafion for theophylline. Under the selected condition using differential pulse voltammetry, the response peak currents had a linear relationship with the theophylline concentrations in two ranges from 1.0 × 10 -8 -1.0 × 10 -6 and 2.0 × 10 -6 -3.0 × 10 -5 mol L -1 with a low detection limit of 6.0 × 10 -9 mol L

Fluorescence Probe Based on an Amino-Functionalized Fluorescent Magnetic Nanocomposite for Detection of Folic Acid in Serum

“…The fluorescence intensity of the Fe 3 O 4 –ZnS:Mn 2+ /SiO 2 –NH 2 nanocomposite decreased with additional FA. Dynamic and static quenching are common fluorescence quenching mechanisms . The K SV will increase with rising temperature in dynamic quenching, and in static quenching, the reverse occurs.…”

Electroanalytical overview: The electroanalytical detection of theophylline

“…Graphene, reported to exhibit potentially useful properties over other carbon based nanomaterials, has motivated many authors to explore this 2D material towards the sensing of theophylline. For example Li et al [48] used graphene-Nafion suspensions drop cast onto GC electrodes with nM detection levels possible using DPV with a 120 s accumulation time. Nafion is utilised to not only help dispersion, keeping the graphene from agglomerating with a high surface area, but also contributed to the adsorption of theophylline.…”

“…Nafion is utilised to not only help dispersion, keeping the graphene from agglomerating with a high surface area, but also contributed to the adsorption of theophylline. The graphene/Nafion sensor was applied to theophylline determination in a pharmaceutical product and aminophylline injection sample [48] . Kesavan and co-workers [49] reported a graphene modified electrode for the selective sensing of theophylline in the presence of inhibitor neurotransmitter antagonist, adenosine.…”

A sensitive theophylline sensor based on a single walled carbon nanotube–large mesoporous carbon/Nafion/glassy carbon electrode

“…Since TP molecules were protonated as a positive ion TPH + (pK a ¼ 8.77) 35 in a 0.1 M H 2 SO 4 , TPH + could be more effectively accumulated on the electrode surface owing to electrostatic attraction. 36,37…”