Dispersive Solid Phase Extraction of Nerve Agent Metabolites from Biomedical Samples Using Functionalized Dendritic Fibrous Nanosilica Spheres

A method for efficient extraction, fast derivatization and sensitive detection of metabolite/hydrolysis products of nerve agents, i.e. alkyl alkylphosphonic acids (AAPAs) using functionalized dendritic fibrous nanosilica spheres (FSQ) utilizing dispersive solid phase extraction (DSPE) from biomedical samples was developed. AAPAs are the unequivocal indicators of exposure to nerve agents and serve as potential and primary biomarkers of exposure. To efficiently extract AAPAs from biomedical samples, the dendritic fibrous nanosilica spheres were modified by grafting quaternary amine moieties on the surface and an anion exchange process performed the extraction. The prepared FSQ was characterized by transmission electron microscopy (TEM), zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The extracted analytes from biomedical samples were derivatized using 3,5-bis(trifluoromethyl)benzyl diazomethane. The obtained derivatives were analyzed using GC-MS/MS (SRM) in NICI mode. The proposed method showed excellent analytical characteristics such as high extraction efficiency of AAPAs from urine samples (60–96%), especially at an ultra-trace level, low detection limits (0.05 ppb/50 ppt) and good linearity (0.1 ppb to 50 ppb).