Colorimetric recognition of fluoxetine and sertraline using citrate-capped gold nanoparticles

A new colorimetric method was developed based on gold nanoparticles (AuNPs) as an optical sensor for fluoxetine (Flx) and sertraline (Ser) in aqueous and micellar media. The drugs caused citrate-stabilized gold nanoparticles (Cit-AuNPs) to aggregate due to hydrogen bonding, resulting in alterations in color and absorption spectra. The impact of several parameters such as pH, reaction time, surfactants, and the concentration of analyte was investigated on the aggregation. Visible absorption spectra revealed that the absorption ratios (A₆₅₀/A₅₂₀ and, A₆₃₀/A₅₂₀) were linear with Flx and Ser in the concentration range of 2–22 nM in the aqueous medium. An improvement in the sensitivity and linear calibration range was observed in a micellar medium within 0.1–1.5 nM with a coefficient of determination of 0.999, under optimal conditions. This strategy was used to quantify Flx and Ser with a detection limit of 0.511–0.543 nM in an aqueous medium and 0.041–0.047 nM in a polyvinylpyrrolidone (PVP) micellar medium without any sophisticated equipment. PVP also had a noticeable influence on the stability of the solutions. The anti-interference performance of the Cit-AuNPs-based detection system for the two drugs was good. The method was effectively utilized to quantify Flx and Ser in pharmaceutical preparations, human urine, and blood serum samples due to its good efficiency, rapid reaction rate, and improved sensitivity with relative standard deviations (RSDs) within 1.3%.