[Progress in preparation of hollow nanomaterials and their application to sample pretreatment].

Sample pretreatment technology plays a vital role in the analysis of complex samples and is key to the entire analytical process. Its main purpose is to separate the substance to be measured from the sample matrix or interfering substances in the sample and to achieve a state in which the instrument can be analyzed and detected. Traditional sample pretreatment techniques include liquid-liquid extraction, liquid-solid extraction, precipitation separation, solvent volatilization-rotary evaporation, filtration, and centrifugation. However, the applications of these methods are limited by their low extraction efficiency, complicated operation, long time consumption, unstable recovery, use of large amounts of organic solvents, and large error rates. Several new sample pretreatment techniques, including solid-phase extraction, magnetic solid-phase extraction, solid-phase microextraction, and dispersive solid-phase extraction, have been developed and rapidly applied to various fields to overcome the shortcomings of traditional sample pretreatment methods. However, the development of adsorbent materials with high selectivity and enrichment capability remains a challenge in sample pretreatment technology, in which adsorbents with excellent adsorption performance are crucial. In recent years, various nanomaterials with remarkable properties have been introduced and applied to sample pretreatment, and numerous nano-extraction materials with diverse functions and high selectivity and enrichment capability have been developed. Hollow nanomaterials are nanoparticles with large voids in their solid shells. Owing to their advantageous properties, which include a large effective surface area, abundant internal space, low density, variety of preparation methods, structural and functional tailorability, short mass transmission path, and high carrying capacity, hollow nanomaterials show great application potential in sample pretreatment. The extraction mechanism of these materials is based on the synergistic effects of