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An electrochemical dopamine sensor was developed by electrochemical modification of a carbon paste electrode with a biocomposite made from poly(3,4-ethylenedioxythiophene) (PEDOT) that was doped with double stranded or single stranded DNA. The resulting conducting biocomposite displays excellent electrocatalytic activity towards the oxidation of dopamine (DA) which is attributed to the presence of the DNA dopant. Under optimum conditions and at a working potential of 300 mV, the modified electrode is capable of detecting DA in the 0.25 to 66 μM concentration range. The detection limit is 74 nM. The sensor is not interfered by uric acid and ascorbic acid. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A sensitive and selective electrochemical sensor for the determination of nitrobenzene (NB) was developed based on a carbon paste electrode (CPE) modified with a nanocomposite prepared from the conducting polymer poly(3,4-ethylenedioxythiophene) and carbon nanotubes. The modified CPE exhibits good conductivity, a large surface area, and excellent catalytic activity towards the electrochemical reduction of NB. Under optimal conditions, the modified CPE is capable of detecting NB in the 0.25 to 43 μM concentration range and with a detection limit at 83 nM. Moreover, the sensor is highly stable and reusable, and free of interferences by other commonly present nitro compounds. It was used to determine NB in wastewater samples. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

An electrochemical sensor for paracetamol is described that consists of a glassy carbon electrode (GCE) that was modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) doped with MnO2 nanoflowers. The hydrothermally synthesized MnO2 nanoflowers possess a large surface area and can be doped into PEDOT through electrochemical deposition to form a conducting polymer nanocomposite. The nanoflowers are shown to be uniformly distributed within the nanocomposite as revealed by elemental mapping analysis. The nanocomposite displays excellent catalytic activity toward the electrochemical oxidation of paracetamol. The modified GCE, best operated at a working potential of around 0.37 V (vs. SCE) has a linear response in 0.06 to 435 μM paracetamol concentration range and a very low limit of detection (31 nM at a signal-to-noise ratio of 3). The sensor exhibits excellent reproducibility and stability, and satisfying accuracy for paracetamol detection in pharmaceutical samples. [ABSTRACT FROM AUTHOR]