Linagliptin electrochemical sensor based on carbon nitride-β-cyclodextrin nanocomposite as a modifier

Linagliptin (LGP) is a novel hypoglycemic drug that belongs to the dipeptidyl-peptidase-4 inhibitor class that was approved in 2011 for the treatment of type 2 diabetes. Today, the integration of different materials and electrochemistry has opened a new horizon to develop highly selective, sensitive, rapid and reliable techniques to detect and quantify such vital analytes. The purpose of this article is to develop an improved carbon paste electrode (CPE) with graphitic carbon nitride/β-cyclodextrin nanocomposite (gCN-βCD/CPE) as an electrochemical sensor for the measurement of LGP. For this purpose, gCN was synthesized from melamine and mixed with βCD to obtain a nanocomposite for the chemical modification of CPE. The influence of modifier on the selectivity, sensitivity, response and lifetime of the CPE was investigated. The results show that the developed LGP electrochemical determination method has a broad range of linearity from 0.01 to 50 μM (R2 > 0.986) based on differential pulse voltammetry (DPV) responses. The detection limit of the method was 3 nM and the probable interference influence on the analytical signal of LGP was insignificant. The improved electrode was successfully used to measure LGP in the blood serum sample with a satisfactory relative recovery (>95.6%).