Which method is the most common means of evaluating radiochemical purity?

The most common means of evaluating radiochemical purity is instant thin layer chromatography (ITLC). This method is widely used in nuclear medicine and radiopharmacy due to its effectiveness, simplicity, and rapid results. ITLC works by separating the components of a mixture based on their movement across a stationary phase (the chromatography plate) in the presence of a solvent. Radiolabeled compounds can be easily visualized after development, allowing for quick assessment of purity by comparing the position of the radiolabel to known standards.

Additionally, the process is relatively easy to perform and requires minimal equipment, making it accessible for routine quality control in a clinical setting. This practicality, combined with its ability to reliably differentiate between labeled and unlabeled forms of a compound, solidifies ITLC's position as the preferred method for evaluating radiochemical purity in most scenarios.