Development of an Amperometric Acetic Acid Sensor in Organic System

An amperometric method was developed by using a lead working electrode in acetonitrile organic solution for detecting acetic acid. The mechanisms of electrochemical reaction were corresponding to the reduction of acetic ions in acetonitrile organic solution. The steady state amperometric current resulted from the reduction of acetic ions to produce the aldehyde in a two-electron process. In the organic sensing system, the organic salt, [CH3(CH2)3]4NBF4, was added into the solution to increase the conductivity of the acetonitrile organic solution. The potential window of limiting current of acetic ion reduction at the lead interface was determined in acetonitrile electrolyte in the range from −1.5 to −2.3 V (vs. Ag/Ag in acetonitrile). The effect of supporting electrolyte concentration on sensitivity was also discussed. The response time of acetic acid in the sensing system was 30 s. Meanwhile the stability of the sensing system was also tested.