Polyvinyl alcohol-citrate-stabilized silver nanoparticles as an optical sensor for selective colorimetric determination of sildenafil.

A facile and sensitive colorimetric detection method for sildenafil citrate (SLDC) has been developed by using polyvinyl alcohol-citrate-stabilized silver nanoparticles (PVA-Cit-AgNPs). The sensitivity and selectivity of colorimetric detection were investigated in detail. The PVA-Cit-AgNPs could be induced to aggregate immediately in the presence of SLDC, especially after the addition of 0.1 M HCl solution. The SLD could be detected by the colorimetric response of AgNPs that could be monitored by a UV-Vis spectrophotometer or even the naked eye. The linear range was found to be 0.6-5.0 μM with the calculated detection limit of 0.1 μM and the naked-eye detection limit was determined as low as 0.6 μM. The proposed method is successfully employed for the determination of SLDC in commercially available tablets. Meanwhile, the excipients present in the pharmaceuticals do not interfere with the assay procedure.