Colorimetric detection of fluoxetine using citrate-capped silver nanoparticles

A novel colorimetric assay has been presented for the detection of fluoxetine using citrate-capped silver nanoparticles (CIT-Ag NPs) as a colorimetric sensor. The detection of fluoxetine was accomplished by observing color change of CIT-Ag NPs solution from yellow to dark brown due to aggregation induced by fluoxetine. The aggregation of CIT-Ag NPs was characterized by various techniques including UV-Vis spectrometry, scanning electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential. A characteristic absorption peak of CIT-Ag NPs at 400 nm was red shifted and surface plasmon resonance band became broad due to addition of fluoxetine. Under optimized conditions, linear calibration curve was obtained within concentration range of 2-10 mu g/ml with detection limit of 0.18 mu g/ml. Furthermore, the developed colorimetric assay was found to be simple, sensitive, reproducible, and selective towards a number of pharmaceutical additives. It involved sensing of fluoxetine by naked eye within few minutes without requiring any complicated instrumentation. Colorimetric platform was applied to detect fluoxetine in pharmaceutical formulation, and biological fluids including spiked human urine and blood serum samples.