LAUSR

Abstract Psidium guajava leaves are laden with potential reducing analytes namely quercitin, chlorogenic acid, d ‑glucose, ascorbic acid and capping agents like citric acid. This work reported on the one-pot synthesis of AgNPs by these analytes extracted in an aqueous medium and the synthesis rate was synergized by microwave (MW). The synergy between the MW input powers and disintegration of capping agents leading to particle aggregation was explored. The modified electrode (AgNPs (pH 9.5)/GPE) exhibited a reduction in charge transfer resistance from 3.2 to 0.453 kΩ. A single electron reaction (Tafel slope 103 mV/decade, α = 0.57) of ascorbic acid (AA, 0.380 V vs. Ag/AgCl) was found in a phosphate buffer media (pH 7.2) and, AA oxidation was diffusion control at AA ≤ 150 μM and activation control at 150 ≤ AA ≤ 2000 μM. Dopamine and uric acid couldn't interfere the response current of the chronoamperometric test of AgNPs(pH 9.5)/GPE and, the (peak)separation potential of 0.272 and 1.114 V was found for AA-dopamine and AA-uric acid. The limit of detection and sensitivities of AgNPs(pH 9.5)/GPE were estimated as 14.63 μM and, 0.719 (diffusion control) and 0.390 (activation control) μA/cm2·μM. The concentration of AA in S. edule and Z. mauritiana extract determined using AgNPs(pH 9.5)/GPE well matched with high performance liquid chromatography.