What is the primary purpose of using Ninhydrin in latent print development?

The primary purpose of using Ninhydrin in latent print development is to react with amino acids present in the sweat and other organic residues found in latent fingerprints. When Ninhydrin is applied to a surface that has been touched by a finger, it reacts with the amino acids to form a colored compound known as Ruhemann's purple, which makes the latent prints visible. This chemical reaction is specifically useful for enhancing prints on porous surfaces, such as paper, where amino acids can be deposited.

By understanding this process, it's clear that the focus on amino acids as a target for the Ninhydrin reaction is what makes this method effective for developing latent prints. Other options do not accurately reflect the core scientific mechanism that Ninhydrin employs in latent print enhancement.