detection of theophylline using molecularly imprinted polymers based on thioglycolic acid-modified cdte quantum dots

Molecularly imprinted polymers (mips) and quantum dots (qds) have been widely employed to fabricate highly sensitive and selective sensor. here, we developed a fluorescence nanosensor based on thioglycolic acid-modified cdte qds that is coated with molecularly imprinted polymers for the specific detection of theophylline (thp). initially, water-soluble thioglycolic acid-modified cdte qds were synthesized by refluxing method. then, mips-coated qds (mips-qds) composite was produced by sol–gel process using thp as a template. therefore, the selectivity of the molecular imprinting technique and advantages of qds were combined. the prepared qds and the mips-qds were characterized using x-ray diffraction technique, transmission electron microscopy, dynamic light scattering, fourier transform infrared spectroscopy, and fluorescence spectrometry. finally, this sensing system was successfully used to detect thp in human plasma samples with recoveries of 90% to 108%. a very good linear relationship was observed between the decreasing in the fluorescence intensity of mips-qds and increasing the thp concentration within concentration range of 0.14–3.05 µmol l−1, with a correlation coefficient of 0.9992 and detection limit of 0.07 µmol l−1.