A new method based on fluorescence spectroscopy for the sensitive determination of aminophylline (AP), an antiasthmatic drug, was developed in this work. Amino-functionalized graphene quantum dots (afGQDs) were synthesized based on a two-step method and they were characterized by transmission electron microscope, UV-vis absorption spectrum and infrared spectrum. The fluorescence of afGQDs was quenched by riboflavin (Rf) via both dynamic quenching and inner filter effect. Photoilluminated Rf-AP system in the presence of oxygen produced hydroxyl radicals (OH). The latter accepted electrons from afGQDs owing to a photo-induced electron transfer process and led to the further fluorescence decline. The changing extent of the fluorescence intensity was found to be proportional to the concentration of AP in the range of 0.10-10 μg mL-1 and the limit of detection arrived at 40 ng mL-1. The proposed method was successfully employed for the determination of AP in a pharmaceutical sample and the recovery rate varied in the range of 99%-106%.

中文翻译：

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基于光照射的核黄素-氨茶碱系统诱导的氨基官能化石墨烯量子点的荧光猝灭测定氨茶碱。

在这项工作中开发了一种基于荧光光谱的灵敏测定抗哮喘药氨茶碱（AP）的新方法。基于两步法合成了氨基官能化石墨烯量子点（afGQDs），并通过透射电子显微镜，紫外可见吸收光谱和红外光谱对其进行了表征。afGQDs的荧光通过动态猝灭和内部滤光作用被核黄素（Rf）猝灭。在氧的存在下，光照射的Rf-AP系统产生羟基自由基（OH）。后者由于光诱导的电子转移过程而接受了来自afGQD的电子，并导致荧光进一步下降。发现荧光强度的变化程度与AP浓度在0范围内成正比。10-10μgmL-1，检出限为40 ng mL-1。该方法成功用于药物样品中AP的测定，回收率在99％-106％的范围内变化。