preparativ

Preparativ, often written as präparativ in German or preparative in English, is an adjective used in chemistry and related disciplines to describe methods and processes intended to prepare and isolate chemical substances on a scale larger than typical analytical experiments. The term emphasizes the production of quantities of material that are suitable for further use, rather than merely for measurement or identification.

Preparative methods differ from analytical ones in purpose and scale. Analytical techniques aim to identify, quantify, or characterize components in small samples, whereas preparative techniques seek to separate, purify, and collect sizable amounts of a target compound. Key performance metrics for preparative work include yield, purity, recovery, and scalability, as well as solvent consumption and cost.

Common preparative approaches include preparative chromatography (such as prep-HPLC and prep-GC), crystallization, distillation, and liquid–liquid or solid–liquid extraction. Preparative chromatography uses larger equipment and columns to obtain purified compounds in milligram to multi-gram or kilogram quantities, depending on the process. Crystallization and distillation rely on differences in solubility or volatility to isolate the desired product.

Applications of preparativ methods are found in pharmaceutical development, natural product isolation, and chemical synthesis scale-up, where sufficient quantities of a pure compound are needed for testing, formulation, or further transformation. Challenges include ensuring adequate purity at scale, managing solvent and energy use, and addressing safety and regulatory considerations.

See also preparative chromatography, purification, and scale-up.