How does separating a mixture differ from purifying a substance?

In chemistry, the terms separation and purification are closely related, as both involve the isolation and refinement of components within a mixture. However, they are distinguished by their primary objectives:1

• Separation is the broader process of altering a sample's composition to isolate or distinguish its various components. This is often performed to facilitate the analysis of specific substances—such as concentrating trace pollutants for monitoring or removing interfering materials that might cause erroneous results.12
• Purification is a specific type of separation focused on isolating a desired substance by removing unwanted contaminants. The goal is to obtain a pure product, which is essential in fields like medicine and manufacturing to ensure safety, uniform potency, and the absence of harmful impurities.2314

While the techniques used for both—such as distillation, crystallization, and chromatography—often overlap, the rigor of purification depends on the intended application. For scientific identification, purification must be carried to the highest degree, whereas practical applications may only require the removal of components that are objectionable, such as unwanted odor, color, or flavor.56