Development of Molecularly Engraved Polymer Based Sensor for Detection of Theobromine in Tea

A low cost sensor has been developed in this work for the detection of theobromine (ThBr) in tea utilizing molecularly imprinted polymer technique. At first, thorough mortaring of the materials prepared by co-polymerization of divinyl benzene (DVB) and polyacrylic acid on a graphite sheet is done. The total and clean removal of theobromine from the polymer matrix has been confirmed through use of ultra violet visible spectroscopic (UV-vis) analysis. The analytical and electrochemical characteristics of the sensor have been determined on application of differential pulse voltammetry (DPV). Acceptable repeatability of the sensor is confirmed with relative standard deviation (%RSD) value of 1.42. The quantitative measure for selectivity is the relative selectivity coefficient (RSC). RSC obtained in this case is 71.43%. Real time usability of the as-prepared electrode has been checked by subjecting it to eight grades of tea. To focus on segregation capability of the sensor based on its theobromine content in tea, a dimension reduction technique like principal component analysis (PCA) was performed using the experimental datasets. A quantitative measure of separation has been evaluated by calculating the separability index (SI). An SI value of 25.69 so obtained affirms a clear segregation among the samples.