Natural adsorbents for sample pretreatment: Mechanism insights, greenness assessment and practical applications

Abstract

Sample pretreatment, as a core component of trace analysis in complex matrices, plays a pivotal role in driving the sustainable development of analytical chemistry through green innovation. Natural adsorbents (N-Ads), represented by natural materials and biowaste such as plant fibers and biochar, have demonstrated immense potential in sample pretreatment owing to their superior environmental compatibility, reusability, and high adsorption efficiency. This review underscores the urgency of addressing key challenges in N-Ads application for sample pretreatment, such as insufficient elucidation of multi-mechanistic synergies, the incompleteness of green assessment systems, and the inadequate interference resistance in complex matrices for N-Ads being applied in sample pretreatment. This work provides a systematic review of the innovative applications of N-Ads in the pretreatment of biological, food, and environmental samples, elaborating on their applications and performance characteristics in various extraction methods including solid-phase extraction, magnetic solid-phase extraction, and solid-phase microextraction. Furthermore, it elucidates the multidimensional mechanisms of adsorbent-analyte interactions and the research methodologies employed. In light of the current inadequacies in the greenness evaluation systems for N-Ads, this review explores the value and potential application of green analytical chemistry indicators in quantifying the greenness of pretreatment methods. By addressing the limitations of traditional reviews, this work reveals critical scientific challenges in adsorbent preparation, application scenarios, mechanistic interpretation, and ecological benefit evaluation through critical analysis, thereby offering interdisciplinary integration pathways for further advancements in N-Ads-based sample pretreatment.