Green Synthesis of Ag/Carrageenan Nanoparticles Using Avocado Leaf Bioreductor (<i>Perseaamericana</i> Mill.) for Colorimetric Detection of Nitrite

Urinary tract infection (UTI) is one of the most common types of infection caused by the growth of microorganisms in the human urinary tract. Nitrite, which results from nitrate degradation by microorganisms in disease, is an indicator in diagnosing UTIs. This research aims to determine the synthesis of Ag nanoparticles (AgNPs) using avocado leaf bioreductors ( Persea americana Mill.) and carrageenan as a stabilizer that can be used for colorimetric detection of nitrites to minimize the use of dangerous and environmentally unfriendly inorganic materials. Characterization and analysis in this research used a UV-Vis spectrophotometer, FT-IR (Fourier Transform Infra-Red), PSA (Particle Size Analyzer), and SEM (Scanning Electron Microscopy). The AgNPs synthesis process was carried out by varying the bioreductant volume and carrageenan concentration. The optimum volume variation results were obtained at 1:1 with a maximum wavelength of 428 nm and an absorption 1.725. In addition, the optimum concentration of carrageenan was obtained at a concentration of 2.5% with a maximum wavelength of 404 nm and an absorbance of 2.582. The results obtained for AgNPs/carrageenan for colorimetric detection of nitrite showed a color change to purple with a LOD value of 0.2402 µM and LOQ of 0.8013 µM