Study of the interaction of 6-mercaptopurine with protein by microdialysis coupled with LC and electrochemical detection based on functionalized multi-wall carbon nanotubes modified electrode

Microdialysis sampling coupled with liquid chromatography and electrochemical detection (LC-ECD) was developed and applied to study the interaction of 6-Mercaptopurine (6-MP) with bovine serum albumin (BSA). In the LC-ECD, the multi-wall carbon nanotubes fuctionalized with carboxylic groups modified electrode (MWNT-COOH CME) was used as the working electrode for the determination of 6-MP. The results indicated that this chemically modified electrode (CME) exhibited efficiently electrocatalytic oxidation for 6-MP with relatively high sensitivity, stability and long-life. The peak currents of 6-MP were linear to its concentrations ranging from 4.0×10^-7 to 1.0×10^-4 mol l^-1 with the calculated detection limit (S/N=3) of 2.0×10^-7 mol l^-1. The method had been successfully applied to assess the association constant (K) and the number of the binding sites (n) on a BSA molecular, which calculated by Scatchard equation, were 3.97×10³ mol^-1 l and 1.51, respectively. This method provided a fast, sensible and simple technique for the study of drug-protein interactions.