Nitrogen-doped NiCo-layered double hydroxide nanocage-based solid phase microextraction for highly selective recognition and sensitive detection of nitrogen-containing pesticides.

Pesticides are indispensable products in agricultural production, poses risks to human health, ecological and environmental pollution due to its bioaccumulation and excessive use. Despite existing detection methods, the need for rapid, sensitive, and specific recognition pesticides quantification remains urgent, particularly for widely used nitrogen-containing pesticides. Here, a nitrogen-doped layered double hydroxide nanocage (N-NiCo-LDH) with hollow-structured composite was conjugated via a simple solvothermal method, it was used as the extraction medium for solid-phase microextraction (SPME), which provided abundant hydrogen bonding interactions for nitrogen-containing pesticides. The adsorption mechanism was discussed through X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Moreover, a sensitive detection method coupled with high-performance liquid chromatography (HPLC) was developed for the efficient extraction of six nitrogen-containing pesticides from real samples. Under optimized conditions, the method demonstrated advantages including low detection limits (0.013-0.315 μg·L), a wide linear range (0.045-1000 μg·L), good reproducibility, and ultra-high adsorption capacity (319.0-50.5 mg·g). This work was based on the inherent mass transfer advantages of hollow materials and achieved specific and efficient adsorption of organic pollutants through structural modification, proposing a novel strategy for applying tailored hollow-structured materials in adsorption, separation applications, identification of subject and object, and related fields.