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Summary form only given. N-acetylcysteine (NAC) commonly known as acetylcysteine, is a pharmaceutical drug and nutritional supplement with numerous uses. Its primary use is as a mucolytic agent. The drug rapidly metabolizes to intracellular glutathione which acts as a powerful antioxidant in the body. Finally, it has been claimed to have a protective effect against cancer for its action as an antioxidant and a glutathione precursor. Acetaminaphen (AC) is widely used as an analgesic anti-pyretic drug with similar effects as aspirin. It is regarded as a suitable replacement for aspirin in patients sensitive to aspirin or those with asthma. Intravenous acetylcysteine is typically administered for the treatment of paracetamol (acetaminophen) overdose. Large quantities of paracetamol causes a minor metabolite called N-acetyl-p-benzoquinone imine (NAPQI) that accumulates in the body and is normally conjugated by glutathione. When taken in excess, the body's limited glutathione reserves fail to inactivate the toxic NAPQI. The metabolite thus produced is then free to react with key hepatic enzymes, damaging hepatocytes. This may lead to severe liver damage and even to death by fulminant liver failure. Due to this fatal effect, simultaneous determination of these compounds (NAC & AC) is very important. However, a major problem is that at bare electrodes, the anodic peak potentials for NAC and AC are almost the same, which results in their overlapped current responses and makes their discrimination very difficult. In this project, a new dopamine-derivative, i.e. N-(3,4-dihydroxyphenethyl)-3,5dinitrobenzamide (N-DHPB), was synthesized and its application was investigated for the simultaneous determination of NAC and acetaminophen (AC) using modified multiwall carbon nanotubes paste electrode. This modified electrode exhibited a potent and persistent electron mediating behavior followed by well separated oxidation peaks of NAC and AC. Differential pulse voltammetry (DPV) - - peak currents of NAC and AC increased linearly with their concentration in the ranges of 0.5-200 μmol L-1 and 15.0-270 μmol L-1 respectively. The detection limits for NAC and AC were 0.2 μmol L-1 and 10.0 μmol L-1 respectively. The relative standard deviation for seven successive assays of 1.0 and 30.0 μmol L-1 NAC and AC were 1.7% and 2.2%, respectively. The proposed sensor was successfully applied for the determination of NAC in human urine, tablet, and serum samples.
Date of Conference: 1-3 Dec. 2010