Development of a colorimetric sensor based on Prussian blue nanoparticles for the determination of phenylephrine

In this thesis, a novel colorimetric sensor based on Prussian blue nanoparticles (PB-NPs) was developed for the rapid, selective, and cost-effective detection of phenylephrine, a substance monitored by the World Anti-Doping Agency (WADA) due to its doping potential. Initially, PB-NPs were synthesized via a chemical precipitation method, and their structural and optical characterizations were performed using Fourier-transform infrared (FT-IR) spectroscopy and UV-visible spectrophotometry. The reaction conditions were optimized, with the optimal parameters determined as pH 6.5, 25 °C, and an incubation time of 15 minutes. The change observed in the optical properties of PB-NPs in the presence of phenylephrine was attributed to the reduction of Prussian blue to Prussian white, resulting from the reaction between phenylephrine and the nanoparticles. Calibration studies showed that accurate quantification of phenylephrine could be achieved within the range of 10–125 μg/mL, with a limit of detection (LOD) of 3.82 μg/mL and a limit of quantification (LOQ) of 12.61 μg/mL. The selectivity of the sensor was evaluated by comparing its response to potential interferents such as tyrosine, ascorbic acid, glucose, and urea, and a high optical response was observed specifically for phenylephrine. The reliability of the method was supported by repeatability and stability tests, with the coefficient of variation remaining below 0.3% in consecutive measurements, and stable signals obtained from the sensor for up to 15 days. In real sample analyses, the sensor successfully quantified phenylephrine in artificial urine matrices with high recovery (97–101%) and low standard deviation. These results demonstrate that the PB-NP-based colorimetric sensor offers a promising, innovative, and practical alternative for the rapid, portable, and economical detection of phenylephrine, particularly for biomedical diagnostics and doping analyses