Harnessing Corn Silk (Zea mays L.) as a Green Analytical Reagent for Sequential Injection Detection of Pb(II) in Wastewater

Abstract

Lead (Pb(II)) contamination in aquatic systems requires analytical methods that are sensitive, rapid, and environmentally responsible. In this study, a Sequential Injection Analysis (SIA) system coupled with UV-Vis detection was developed using corn silk (Zea mays L.) extract as a natural complexing reagent for Pb(II). The analytical procedure was evaluated with respect to reagent stability, pH, reaction time, and flow rate. The Pb(II)-corn silk complex showed a maximum response at 672.4 nm. The extract remained stable for 10 days, the optimum pH was 4.0, the optimum reaction time was 10 s, and the optimum flow rate to the detector was 200 μL/s. The calibration curve was linear over 0–0.88 mg/L Pb(II), with R² = 0.9959 and a detection limit of 8.99 μg/L. The method was applied to three water/wastewater samples and produced recoveries of 90–98%. The SIA approach uses small solution volumes and automated flow handling, supporting the principles of green analytical chemistry. The study also identifies the fixed sample-to-reagent volume ratio used in the original experimental procedure and the absence of an experimental interference study as limitations that should be addressed in further validation.