Functionalized porous carbon microspheres packed column for solid phase extraction and preconcentration of trace metal ions in food and water samples

Abstract

Porous materials play a crucial role in the extraction of trace analytes; yet, the attainment of high selectivity and efficient regeneration continues to pose a considerable problem. In this study, we employed a green method to synthesize porous carbon microspheres. These microspheres were subsequently functionalized with aminophosphonic acid to facilitate the extraction of heavy metal ions from real samples. A comprehensive analysis of the aminomethylphosphorylated carbon microspheres was conducted using FTIR, SEM, EDX, TEM, BET and water contact angle measuring techniques. The potential optimization of analyte enrichment can be accomplished by the proposed solid-phase extraction (SPE) approach, which notably reduces spectrum interferences following sample purification. Following the IUPAC equation, the detection limit of the proposed method was found to be 0.04 ng mL⁻¹, after running 20 replicate blank tests. The primary focus of sequestration of trace metal ions is the formation of metal–ligand chelates within the carbon spheres, resulting in enhanced selectivity and extraction rates exceeding 99.9% from samples with low concentrations. The present studies show a significant preconcentration limit of 0.4 ng mL⁻¹ and a substantial preconcentration factor of 500. The method was implemented to examine real food and water samples, and the obtained data exhibit significant accuracy with a relative standard deviation (RSD) of less than 5%.