Covalent organic nanospheres as a fiber coating for solid-phase microextraction of genotoxic impurities followed by...

Covalent organic nanospheres (CONs) were explored as a fiber coating for solid-phase microextraction of genotoxic impurities (GTIs) from active ingredients (AIs). CONs were synthesized by an easy solution-phase procedure at 25 °C. The obtained nanospheres exhibited a high specific surface area, good thermostability, high acid and alkali resistance, and favorable crystallinity and porosity. Two types of GTIs, alkyl halides (1-iodooctane, 1-chlorobenzene, 1-bromododecane, 1,2-dichlorobenzene, 1-bromooctane, 1-chlorohexane, and 1,8-dibromooctane) and sulfonate esters (methyl p-toluenesulfonate and ethyl p-toluenesulfonate), were chosen as target molecules for assessing the performance of the coating. The prepared coating achieved high enhancement factors (5097-9799) for the selected GTIs. The strong affinity between CONs and GTIs was tentatively attributed to π-π and hydrophobicity interactions, large surface area of the CONs, and size-matching of the materials. Combined with gas chromatography-mass spectrometry (GC-MS), the established analytical method detected the GTIs in capecitabine and imatinib mesylate samples over a wide linear range (0.2-200 ng/g) with a low detection limit (0.04-2.0 ng/g), satisfactory recovery (80.03%-109.5%), and high repeatability (6.20%-14.8%) and reproducibility (6.20%-14.1%). Therefore, the CON-coated fibers are promising alternatives for the sensitive detection of GTIs in AI samples.