Preanodized Screen Printed Carbon Electrode for Detection of Linalool using Three Terminal Network

Abstract

Linalool is a very important flavouring compound found in plants which is used in food and beverages. Linalool has been traditionally detected by analytical instruments such as gas chromatography (GC) coupled with mass spectroscopy(MS) which are not suitable for routine tests. For fast and low cost detection of chemical compounds electrochemial sensors are most suitable. Screen printed carbon electrode (SPCE) is one of the most popular and low cost device used for detection of chemical compounds. In this article we present the detection of linalool using a low cost preannodized commercial screen printed carbon electrode (SPCE). Traditionally electrochemical sensors are used in two terminal mode, however three terminal analysis of electrochemical sensors are found to be more rationale and accurate. In this paper we have analyzed detection of linalool by an advanced three terminal analysis. First we have performed cyclic voltammetry(CV) of the SPCE which showed clear oxidation peaks at different concentration of linalool. The input-output data of the CV has been used for analysis of the impedance of the SPCE.The impedance model of the SPCE was estimated by autoregressive moving average with exogenous inputs(ARMAX) modelling technique using the CV data. The three terminal impedance fitting revealed the values of electrical parameters and the parasitic elements at different linalool concentration. The stability limits of the SPCE was also determined from the pole-zero and Nyquist plots of the estimated models. Impedance behaviour to frequency of the SPCE was further analyzed by impedance plot( 𝒁 vs −𝒁 ′ ) from which we are able to relate the CV scan rate to the impedance of the SPCE. Finally the sensitivity and repeatability of the SPCE was determined using a measurement circuit.