Voltammetric Determination of Alkaloids and Metabolites: From Structural Classification to Bioanalytical Applications...

Alkaloids represent one of the most significant classes of compounds of natural and synthetic origin due to their pronounced biological activity and broad applications in pharmacy, medicine, and toxicology. Their determination in complex matrices such as biological fluids or pharmaceutical formulations necessitates the use of highly sensitive, selective, and reliable analytical techniques. Among these, electrochemical methods, particularly voltammetry, provide rapid, cost-effective, and precise detection. This review systematically evaluates voltammetric approaches for the determination of alkaloids and their metabolites, with a particular focus on studies published over the last two decades (2005-2025). More than 90 publications have been critically analyzed, covering voltammetric methodologies applied to 26 alkaloids and their metabolites, and highlighting key trends in electrode selection, experimental conditions, and strategies to enhance analytical performance. Special emphasis is placed on linking the electrochemical behavior of alkaloids to their chemical structure and functional group affiliation, providing insights into reaction mechanisms and detection sensitivity. The review also incorporates illustrative schemes of representative alkaloids and their electrochemical transformations, demonstrating practical applications for pharmaceutical analysis, food safety, and forensic monitoring. By critically assessing the strengths and limitations of current methodologies, this work offers a valuable resource for researchers and professionals in electroanalytical chemistry, pharmaceutical sciences, biomedicine, and toxicology, supporting the development of more selective and efficient voltammetric techniques for alkaloid investigation.