Conducting polymer modified screen-printed carbon electrode coupled with magnetic solid phase microextraction for determination of caffeine.

In the current study, we introduce magnetic solid phase microextraction coupled with electrochemical detection of caffeine. A commercially available disposable screen-printed carbon electrodes modified with poly Alizarin Red S are employed as electrochemical sensors in the detection stage. However, the suitability of magnetic solid phase microextraction for electroanalytical methods such as square wave voltammetry has not been declared. With our optimised conditions in hand, the system response was linearly proportional to the concentration of caffeine in the range of 0.5-20µM with a correlation coefficient of about 0.9987. The detection limit of the sensing system was found to be 0.05µM (a signal-to-noise ratio of 3). At the end of the study, the suitability of this new procedure for the analysis of energy drink, soft drink, and chocolate milk samples was demonstrated.