Detection of thiocholine ions with cobalt phthalocyanine mediated screen printed electrode

Abstract

Acetylcholine (ACh) is a neurotransmitter that is responsible for many of our bodily functions while acetylcholineesterase (AChE) is its enzyme. Certain nerve agents inhibit AChE to cause malfunctions of our body system. To detect those agents, the concentration of AChE by-product, choline, is used as a detection marker. Using a screen printed electrode and acetylthiocholine (ATCh) as a replacement for ACh, amperometry is employed to detect the concentration of the AChE-ATCh reaction by-product, thiocholine. Results showed that 0.1 V is the optimum potential for thiocholine detection. Voltages of 0.2 V and 0.3 V also produced similar current magnitudes. From 0.225 mM to 0.9 mM of thiocholine, the amperometry current exhibits a linear relation with concentration. The sensitivity electrode is around 2.53 mu A/mM. A flow rate of 100 mu L/min is chosen as it is close to the saturation oxidation rate of the electrode and is useful in practical situations. Taking into account the errors met at 0.1 V, the sensitivity of the system is calculated to a minimum of 0.04 mM.