Coupling highly conductive covalent organic framework with nitrogen doped carbon nanotubes enables simultaneous and sensitive quantification of xanthine and hypoxanthine

A highly conductive covalent organic framework (HEX-COF) coupled with nitrogen doped carbon nanotubes (N-CNTs) was prepared and employed to selectively and simultaneously quantitate xanthine (XA) and hypoxanthine (HX). The basic characterizations such as TEM, FT-IR, PXRD and XPS were identified to confirm the morphology, structure, composition properties of HEX-COF/N-CNTs nanocomposites. Further electrochemical investigations showed that HEX-COF/N-CNTs nanocomposites modified electrode enabled simultaneous assay of XA and HX sensitively. Under optimal conditions, the low detection limits can be obtained with the value of 0.031 μM and 0.126 μM for XA and HX, respectively. The linear ranges for XA and HX were 0.1 to 100 μM and 0.5 to 500 μM. With excellent selectivity, repeatability and stability, the proposed approach was successfully adopted to quantitate XA and HX in human urine and fish meat with recoveries of 98.2%–104.9%. The work provided a simple method to detect XA and HX simultaneously.