selective optical detection of citalopram using a fluorescent probe based on carbon quantum dots embedded in silica molecularly imprinted polymer

Abstract: citalopram is a selective serotonin reuptake inhibitor used to treat major depressive disorder, obsessive compulsive disorder, panic disorder, and social phobia [1]. aggregation of citalopram in the body leads to dangerous side effects, including diarrhea, drowsiness, headaches, insomnia, nausea, and many sexual side effects in about 70% of patients taking this drug [2]. regarding the wide use of citalopram, quantification of this medicine and its metabolites has great importance -. this study introduces a sensitive optical nano-sensor based on carbon quantum dots (cqds) embedded in silica molecularly imprinted polymer (smip) for the detection of citalopram in biological samples. this fluorescent nanosensor was made by the polymerization of silica polymer in the presence of cqd nanoparticles as the fluorescent materials and citalopram as the template molecule [3]. after polymerization, template molecules were removed, and cavities, which were similar to citalopram in shape and size, were maintained in the polymeric matrix. the synthesized nanocomposite of cqds embedded in smip (cqds-smip), showed a strong fluorescence emission at 420 nm in the absence of the template molecule. when citalopram was added to the nanostructure, the fluorescence intensity was quenched. the correlation between the extent of quenching in fluorescence emission and the concentration of the added citalopram provided a highly sensitive and selective nano-sensor for the detection of citalopram. the synthesized materials were characterized using fourier transform infrared (ftir), uv-visible (uv/vis) and fluorescence spectrophotometry, high-resolution transmission electron microscopy (hr-tem), and field emission scanning electron microscopy (fesem). the prepared nano-sensor responded to the different concentrations of citalopram with a low detection limit of 3.10 μg.l-1 over a linear range of 100 to 700 μg.l-1, and the relative standard deviation (rsd) was 3.15% (n=3). this nano-sensor was applied to analyze pharmaceutical formulations of citalopram in plasma and human urine samples with remarkable results.