Sensitive stripping voltammetric determination of an anthracene-isatin Schiff base in biological samples

In the present study, the electrochemical behavior and quantitative determination of the Schiff base 3-[(anthracen-2-yl)imino]-5-nitro-1,3-dihydro-2H-indol-2-one (ANT) were investigated for the first time using voltammetric techniques at a glassy carbon electrode. The effects of solvent composition, pH, and scan rate on the redox behavior of ANT were systematically evaluated. The compound exhibited an irreversible oxidation process governed by adsorption-controlled kinetics. Quantitative analysis was conducted using differential pulse stripping voltammetry (AdS-DPV) and square-wave stripping voltammetry (AdS-SWV) under optimized conditions. Both methods exhibited linear responses over the concentration range of 0.2-8.0 μM, with limits of detection of 0.0366 μM and 0.0433 μM for AdS-DPV and AdS-SWV, respectively. The precision of the methods was confirmed through intra- and interday measurements, with relative standard deviations below 1.73%. Recovery studies performed in protein-free human serum yielded 99.78% and 99.52% recoveries for AdS-DPV and AdS-SWV, respectively, demonstrating their applicability to biological matrices. Mechanistic studies using 5-nitroisatin and indomethacin as model compounds indicated that ANT predominantly undergoes oxidation at the anthracene core, an outcome influenced by the nitro group, rather than at the isatin moiety. Collectively, the results reveal the developed voltammetric procedures to be simple, selective, sensitive, and reproducible, providing robust and reliable tools for the electrochemical analysis of this anthracene-isatin Schiff base derivative in biological matrices.