Voltammetric sensors based on mesoporous graphitized carbon black and cyclopentadiene derivatives for determination and recognition of clopidogrel enantiomers

To recognize and determine the enantiomers of clopidogrel, a sensor system based on a glassy carbon electrode modified with Carbopack X mesoporous carbon black and cyclopentadiene derivatives – (1S)-2-cyclopenta-2,4-dien-1-yl-1,7,7-trimethylbicyclo[2.2.1]heptane; (1S, 2S, 4R)-2-cyclopenta-1,3-dien-1-yl-1-isopropyl-4-methylcyclohexane; 9-[(1S,2S,5R)-2-isopropyl-5-methylcyclohexyl]-9H-fluorene. Due to the unique properties of Carbopack X, such as large surface area and high conductivity, it was possible to obtain a mechanically stable and sensitive sensor layer that firmly retains chiral selector molecules on its surface. The morphological, electrochemical and analytical properties of the obtained sensors were studied by scanning electron microscopy, electrochemical impedance spectroscopy, cyclic and differential pulse voltammetry. The determination of clopidogrel enantiomers in biological fluids has been carried out; linear dependences of oxidation peak currents on their concentration in solution for all sensors are preserved in the concentration range from 1 × 10–6 to 5 × 10–4 M. The sensors are cross-sensitized, which allowed combining them into a sensor system with high enantioselectivity and sensitivity towards clopidogrel enantiomers. With the proposed sensor system, the probability of correctly recognizing samples increases compared to single sensors. In all cases, the content of R-clopidogrel in the mixture is correctly determined with a relative error not exceeding 9% and a degree of discovery ranging from 96 to 102%.