A green SPE sorbent based on butterfly pea anthocyanin extract immobilized on Amberlite XAD-1600N for Pb(ii) determination by FAAS

Abstract

Lead contamination in seafood poses a significant risk to human health, necessitating reliable and environmentally sustainable analytical methods for routine Pb(II) monitoring. In this study, a sustainable solid-phase extraction (SPE) method was developed for the preconcentration and determination of Pb(II) using a bio-derived chelating resin prepared by immobilizing anthocyanins extracted from Clitoria ternatea (butterfly pea) flowers onto Amberlite XAD-1600N. Pb(II) retained on the functionalized resin was eluted and determined by flame atomic absorption spectrometry (FAAS). Key operational parameters, including solution pH, loading time and volume, eluent concentration and volume, and sorbent mass, were systematically optimized. Maximum Pb(II) retention was achieved at pH 6.0, and efficient elution was obtained using 5 mL of 1.50 mol L⁻¹ HNO₃. The method provided a detection limit of 0.069 mg L⁻¹ and acceptable overall precision, with a relative standard deviation of 6.6% (n = 20). Owing to the use of plant-derived ligands, low reagent consumption, and the absence of hazardous organic solvents, the method aligns well with the principles of green analytical chemistry. The validated procedure was successfully applied to digested shrimp and squid samples, demonstrating its practicality and suitability for routine, eco-friendly monitoring of Pb(II) contamination in seafood.