Covalent organic framework-based solid phase microextraction coupled with electrospray ionization mass spectrometry...

Bile acids, a representative diagnostic indicator of liver function, are used to visualize the extent of liver injury. Numerous studies have shown that triclosan (TCS) exposure leads to abnormal bile acid metabolism. As a result, there is a requirement to develop a fast and smart means to quantitatively monitor abnormal bile acids from exposure to triclosan in bio-sample. In this work, solid-phase microextraction (SPME) probes of sea urchin-like covalent organic frameworks (COF) were in situ synthesized on steel needles by using 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde (DMTP) as two organic units and employed for extraction of bile acids. This TAPB-DMTP-COF-SPME possessed an excellent specified surface area (3351 m² g^-1) and a high regular porosity (∼3.6 nm), which was an ideal adsorbent to concentrate bile acids efficiently. The created probe, together with electrospray ionization mass spectrometry (ESI/MS), proved to be a fast and specific assay for the detection of bile acids in bio-samples. The proposed method had a low limitation of detection (0.03 μg L^-1), good linearity (R² ≥ 0.9931), wide linear range (0.10-1000.00 μg L^-1) and excellent enrichment factor (63.60-252.00). Based on these excellent properties, it was successful application for the analyzing of bile acids in mice liver and feces, demonstrating the great potential of TAPB-DMTP-COF-SPME-ESI/MS in bile acids detection and liver injury diagnosis.