▎ 摘　　要

In this work, we aim to develop a highly sensitive sensor for the electroanalytical determination of the theophylline (THP). We have developed a new sensor by packing the matrix of cholesterol (CHE), graphene oxide (GO) loaded carbon paste in a polytetrafluoroethylene (PTFE) tube, and used for investigation. Our study shows that as compared to the carbon paste electrode (CPE) the modified sensor was sensitive with a detection limit of 4.45 nM. The adsorption controlled mechanism of the THP in the sensor process was involved with two numbers of electrons and protons. Effect of pH study shows the highest peak current at pH 6.0. Other physicochemical factors were calculated by studying the scan rate effect. The interference of excipients and metal ions with THP was investigated to check the sensitivity and selectivity of the modified sensor. To check the efficiency and realtime application, we applied this sensor in the analysis of THP in the tablet sample and discovered that, the new fabricated sensor has significant detection capacity with good recovery.