Ninhydrin is widely used in forensic science for detecting fingerprints on porous surfaces like paper. It reacts with amino acids present in sweat residues, producing a purple compound known as Ruhemann's purple, which makes latent fingerprints visible.

In biochemistry, it serves as a reagent to detect and quantify amino acids and proteins. It is particularly useful in chromatography for visualizing amino acids after separation.

Additionally, ninhydrin is employed in agriculture to assess the quality of seeds by detecting free amino acids, which can indicate seed viability and health.

It also finds application in the food industry to monitor protein content and detect spoilage by measuring amino acid levels in products.

Overall, ninhydrin is a versatile reagent with significant roles in forensic analysis, biochemical research, agriculture, and food quality control.