Voltammetric determination of trace amount of acetaminophen at the surface of a graphite electrode modified with multi-walled carbon nanotube / surfactant

Carbon nanotubes are a new kind of solid, with two types of structures single-walled and multi-walled (SWCNTs and MWCNTs, respectively). They have been of great interest to researchers over the past decade because of their remarkable properties like high surface area, electrical conductivity, good chemical stability and very high mechanical strength [1]. Carbon nanotubes (CNTs) have been widely used to improve the sensitivity of a variety of sensors in electroanalysis, due to their unique structural and electronic properties [2]. In addition to enhanced electrochemical reactivity, CNT-modified electrodes have been shown useful to accumulate important biomolecules [3]. However, one difficulty for the potential applications of carbon nanotubes is the impediment of dispersing them. Individually suspended carbon nanotubes in different surfactants were reported recently, showing improved dispersion [1].On the other hand, surfactants have proven effective in the electroanalysis of biological compounds and drugs. For example, it was recently shown that surfactants are highly effective in stabilizing the voltammetric response of serotonin by keeping the electrode surface from fouling [4].Drug analysis plays important roles in drug quality control, and has great impacts on public health [5]. Acetaminophen or paracetamol (ACOP) is an antipyretic and analgesic drug widely used, it is an effective and safe analgesic agent used worldwide for the relief of mild to moderate pain associated with headache, backache, arthritis and postoperative pain. So it is very important to establish a simple, fast, sensitive and accurate detection method for ACOP. Many methods have been described for the determination of ACOP, such as titrimetry [6], chromatography, fluorometry, UV spectrophotometry, and various modes of electrochemistry. To the best of our knowledge, very little has been reported on voltammetric determination of acetaminophen. In this work, multi-walled carbon nanotubes (MWCNT) – sodium dodecyl ssulfate (SDS) film coated graphite electrode (GE) for the determination of Acetaminophen was structured. The enhanced electrooxidation and voltammetry of acetaminophen at the surface of MWCNT - SDS film coated GE in Britton-Robinson (B-R) buffer solution (pH 9.0) was attributed to the unique properties of MWCNTs such as large specific surface area and strong adsorptive properties providing more reaction sites. The suggestive method was successfully used to determine acetaminophen in acetaminophen tablets