Comparative Analysis of the Optical Properties of Silver Nanoparticles Synthesized Using Tomato and Cabbage Extracts

This study presents the use of tomato ( Solanum lycopersicum ) and cabbage ( Brassica oleracea ) extracts as reducing and capping agents in the synthesis of silver nanoparticles. During synthesis, key parameters including reaction time, extract‐to‐precursor volume ratio, initial silver nitrate (AgNO 3 ) concentration, and type of extract were varied. The resulting AgNPs were characterized using UV–Visible (UV–Vis) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and antibacterial assays. The experimental UV–Vis data were correlated with Mie theory simulations to estimate nanoparticle diameter, extinction efficiency, and number of particles per unit volume. In addition, a mathematical relation between surface plasmon resonance (SPR) and the size of the nanoparticle was derived from previous experimental works to estimate the size of the nanoparticle. The results demonstrate that tomato extract is a more effective agent for producing smaller, more monodisperse nanoparticles, producing AgNPs with an average diameter of approximately 48 nm and a sharp SPR peak at 419 nm. In contrast, cabbage extract produced larger, more polydisperse nanoparticles with an average diameter of 62 nm and a broader SPR peak around 434 nm. FTIR analysis confirmed the role of functional groups from the plant extracts in the reduction and stabilization of the nanoparticles. Furthermore, the synthesized AgNPs exhibited significant antibacterial activity against Escherichia coli , Staphylococcus aureus , and Pseudomonas aeruginosa . This work underscores that the choice of plant extract and the precise control of synthesis conditions are critical for tailoring the size, stability, and functional properties of AgNPs for targeted applications in areas such as biomedicine and water purification.