One-step fabrication of COF-coated melamine sponge for in-syringe solid-phase extraction of active ingredients from traditional Chinese medicine in serum samples

In this study, a covalent organic framework (COF)-TpBD-supported melamine sponge (MS) was fabricated through a one-step hydrothermal method. The obtained monolithic column was then applied in in-syringe solid-phase extraction (IS-SPE) for the separation of three volatile ingredients from serum samples. Given credit for the superior adsorption capacity of the COF and the homogeneous microporous property of MS, the developed column exhibited satisfactory separation of the targets. And the dominating adsorption mechanism was the hydrophobic interaction forces between TpBD and targets and the high mass transfer efficiency provided by the large pore structure of MS. The results of dynamic adsorption showed that the MS@TpBD column displayed much better adsorption performance than blank MS and TpBD. And it has featured great reusability up to 5 cycles and obtained satisfied recovery values (87.9 ~ 110.3%) in serum samples. As a result of sample clean-up, this column offers low limit of detections (LODs) down to 0.014, 0.010, and 0.020 μg/mL, respectively. In summary, we believe that this convenient separation column has prominent application promise in the fields of separating activity ingredients in biological samples.