Natural fibers as sustainable and renewable materials for green sample preparation

The rise of green chemistry has underscored the importance of eco-friendly sample preparation methods. Natural fibers, both plant-based (such as cotton, kapok, coconut husk, poplar catkin, luffa cylindrica, sisal, and bamboo) and animal-based (including silk, feather, and wool), are celebrated for their unique properties and sustainability. These fibers are increasingly favored in green sample preparation, owing to their environmental benefits and distinct characteristics. This review spans the use of natural fibers from 2004 to 2024, focusing particularly on sample preparation techniques. Predominantly, these materials have been employed as carriers in supported liquid-phase extraction and as sorbents in solid-phase extraction and microextraction, among other uses. Modified materials based on natural fibers are also briefly covered. The review highlights challenges and future prospects of natural fibers in sample pretreatment, encouraging their use to develop sustainable analysis methods.