Application of Molecularly Imprinted Poly-Itaconic/Multiwalled Carbon Nanotubes for Selective and Sensitive Electrochemical Detection of Linagliptin

In this work, we report the first molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of the antidiabetic drug Linagliptin (LNG) in pure sample, tablets, and spiked human urine and serum samples. Using a graphite electrode, differential pulse voltammetry (DPV) was applied to study the electrochemical behavior of LNG in a Britton Robinson (BR) universal buffer of pH 8 with Ag/AgCl electrode and Pt wire. The sensor is based on the modification of the traditional carbon paste sensor with Itaconic acid (IA) as monomer, which cross-linked using ethylene glycol dimethacrylate (EGDMA) and multiwalled carbon nanotubes (MWCNTs) as a modifier. The different factors were optimized, such as ratio of MIP components, percentage of multiwalled carbon nanotubes (MWCNT), pH, accumulation time, accumulation potential and scan rate. The proposed sensor was characterized morphologically using: Scanning electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) and electrochemically applying electrochemical impedance spectroscopy (EIS)and cyclic voltammetry (CV). DPV was applied to obtain the calibration curve and optimization of different factors, the proposed sensor shows a wide linear range of 1 x 10(-12)M (0.47 ng l(-1)) to 1 x 10(-7)M (47.26 mu g l(-1)) and limit of detection (LOD)1 x 10(-13)M (0.05 ng l(-1)) while the limit of quantification (LOQ)was found to be 3.3 x 10(-13)M (0.16 ng l(-1)) in addition to good reproducibility and selectivity.