In this study we introduce a novel modification for the surface of screen-printed electrode (SPE) by graphene quantum dot (GQD) in order to be used in the determination and detection of theophylline. An uncomplicated technique was employed to stabilize GQD on screen-printed electrode. Function evaluation of the GQD modified SPE (GQD/SPE) by cyclic voltammetry revealed enhanced electroactivity in the oxidation of theophylline in buffer solution of phosphate. Differential-pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry were applied to determine the sensitivity of GQD/SPE toward detection of theophylline. A wide linear concentration range of 1.0– 700.0 μM and detection limit of 0.2 μM (S/N = 3) obtained under optimized conditions. This sensor was successful in the assessment of theophylline in real samples.
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机译：在这项研究中，我们介绍了一种通过石墨烯量子点（GQD）对丝网印刷电极（SPE）表面进行的新型修饰，以便用于茶碱的测定和检测。使用简单的技术来稳定丝网印刷电极上的GQD。通过循环伏安法对GQD修饰的SPE（GQD / SPE）进行功能评估，发现在磷酸盐缓冲液中茶碱的氧化过程中电活性增强。应用差分脉冲伏安法（DPV），循环伏安法（CV）和计时电流法测定GQD / SPE对茶碱检测的敏感性。在优化条件下获得的宽线性浓度范围为1.0–700.0μM，检测极限为0.2μM（S / N = 3）。该传感器成功地评估了实际样品中的茶碱含量。
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