Propranolol chiral analysis using voltammetric sensor based on triterpenoid-graphene oxide hybrid material

Abstract

Enantioselective sensors are potentially in demand at all stages of the production, storage and use of drugs, including identifying impurities of undesirable isomers and improving stereoselective synthesis methods. A key aspect for enantioselective sensors design is the development of appropriate molecular architectures that make it possible to create recognition sites with different affinities for enantiomers. This experimental work proposes a new chiral sensor based on glassy carbon electrode (GCE) modified by graphene oxide (GO) covalent functionalized with pentacyclic triterpenoid betulonic acid (BetA) for voltammetric recognition and determination of propranolol (Prop) enantiomers. Characterization of the materials was carried out using FTIR spectroscopy, scanning electron microscopy and cyclic voltammetry. Differential pulse voltammetry was used for Prop enantiomers recognition and quantification. The potential difference reached 30 mV along with enanitoselectivity coefficient ipS/ipR equal to 1.30. The calculated binding energy for S-Prop/GO-BetA complex is higher by 4.801 kcal moll−1 compared to R-Prop/GO-BetA indicating a more favorable mutual arrangement of molecules. The linear determination range was established as 5.0 × 10-6 ∼ 1.0 × 10-4 mol·L-1 and 1.0 × 10-4 ∼ 4.0 × 10-4 mol·L-1 for both enantiomers. The detection limits were determined to be 3.9⋅10-7 mol·L-1 and 5.0⋅10-7 mol·L-1 for S-Prop and R-Prop, respectively. The standard spike-recovery tests were carried out in human biological fluids with recoveries 97.3 % − 106.9 % for both enantiomers. The proposed sensor was used to determine the ratio of Prop enantiomers in mixture by regression analysis with projection to latent structures (PLS). The purpose was to build a PLS-model based on a calibration set containing a known number of Prop enantiomers and recognize a test set prepared independently. All samples of test set are correctly identified and the RSD did not exceed 8.7 %. GCE modified by covalent functionalized GO with BetA showed better stability compared with noncovalent functionalization in terms of electrode degradation.