Comparative evaluation of urine, whole blood, and serum as biological matrices for human biomonitoring of neonicotinoid insecticides and metabolites.

Neonicotinoid insecticides (NEOs) and their metabolites have become ubiquitous environmental contaminants, but the optimal biological matrices for reliable human biomonitoring remain undefined. This study comprehensively characterized twelve neonicotinoid-related compounds, comprising six parent insecticides and six metabolites, in matched urine, whole blood, and serum specimens from 70 participants in southern China. A matrix scoring framework integrating analytical performance, descriptive statistics, and cross-matrix correlations revealed scores ranging from 0.24 to 0.91, highlighting pronounced matrix-dependent variability in extraction efficiency, reproducibility, and toxicokinetic relevance. Urine consistently yielded the highest performance and was identified as the optimal matrix for imidacloprid, thiamethoxam, clothianidin, acetamiprid, dinotefuran, imidacloprid-olefin, desmethyl-thiamethoxam, and desmethyl-acetamiprid, reflecting efficient renal elimination of both parent and metabolized forms. Whole blood best represented thiacloprid, 5-hydroxy-imidacloprid, and 1-methyl-3-(tetrahydro-3-furylmethyl) urea due to their systemic persistence, while serum showed relative advantages for 6-chloronicotinic acid and partially for dinotefuran, associated with protein-binding equilibria. The proposed scoring framework establishes a quantitative foundation for selecting optimal matrices in NEOs biomonitoring and enhances future exposure and health risk evaluations.