What are the implications for primary and secondary amines in their reaction with ninhydrin?

Primary amines react with ninhydrin to produce a deep blue-purple color due to the formation of a colored complex, which is useful for detecting amino acids and peptides. Secondary amines also react, but typically yield a less intense color compared to primary amines. This difference in reactivity can be utilized in analytical chemistry to distinguish between primary and secondary amines in various samples. Tertiary amines do not react with ninhydrin, highlighting the specificity of this reaction in identifying amine types.