Abstract
A new carbon paste electrode for the determination of theophylline in different kinds of tea extracts was designed. The proposed sensor was based on the use of tert-Butylcalix[4]arene-tetrakis(N, N-dimethylacetamide) as a sensing ionophore in the presence of MWCNTs-CuO nanohybrid as an efficient transducer. The fabricated sensor displayed a linear response over the concentration range of 1 x 10(-2)-1 x 10(-7) M of theophylline with LOD of 2.5 x 10(-8) M and Nernstian slope of 58.36 mV/decade. It was characterized by a high level of selectivity, stability, and fast response time (< 10 s) with no surface renewal action. The CPE was efficiently applied for the determination of THP in different kinds of tea extract. The accuracy of the sensor was studied with the aid of the standard addition method. It showed acceptable recovery ranging from 92.00% to 99.63% that indicate the reliability and the efficiency of the proposed sensor.