Colorimetric Analysis of Captopril on the Basis of Its Free Radical Scavenger Character with Carbon Nanozymes as Catalyst

A simple colorimetric method for the measurement of captopril (CAP) on the basis of its radical restoration character was designed. In this system, carbon dots (CDs), having peroxidase mimetic activity, were applied as effective nanozymes. The blue-colored free cation radicals (lambda(max) = 653 nm) were generated via oxidizing 3,3,5,5-tetramethylbenzidine (TMB) by H2O2 in the presence of CDs as catalyst. The principal function of CDs was to improve the cation radical (TMBGreek ano teleia(+)) production and consequently enhance the sensitivity of the method. Captopril was able to inhibit the formation of TMBGreek ano teleia(+). The UV-Vis spectroscopy was utilized to follow how concentration of CAP may impact on the absorption magnitude of the produced TMBGreek ano teleia(+). The linearity range of the calibration graph was from 0.50 to 9.0 mu g mL(-1) (2.3-41.4 mu mol L-1), with a correlation coefficient of 0.9987, when the optimum experimental conditions were utilized. The LOD of the method was determined as 0.12 mu g mL(-1) (0.55 mu mol L-1). The analysis of CAP in pharmaceutical preparation was successfully achieved in this method.

Automated summary

A simple colorimetric method for the measurement of captopril based on its radical restoration character was designed. Carbon dots were used as effective nanozymes to enhance sensitivity. The method successfully analyzed captopril in pharmaceutical preparations.