With the Amino Acid Fingerprints Demonstration Kit, explore one of the simplest and most common methods of developing “latent” fingerprints—invisible fingerprints left behind on porous surfaces, such as paper and cloth.
Demonstrate one of the simplest and most common methods of developing “latent” fingerprints—invisible fingerprints left behind on porous surfaces, such as paper and cloth. Latent fingerprints are composed of several chemicals that are naturally present in skin oils or released through the pores of the skin by perspiration. Ninhydrin, a colorless organic compound, reacts with amino acids found in skin oils to form a bright purple product. The resulting purple “amino acid fingerprints” can then be photographed and processed. In this demonstration, student volunteers make invisible fingerprints on a special blotting paper. The fingerprints are then developed by spraying the paper with ninhydrin solution and heating the product. Use the water soluble ink pad provided with the kit to make a second set of fingerprints for identification purposes. A great activity to show the science behind forensic investigations!
Concepts: Amino acids, ninhydrin reaction, fingerprinting. Time Required: 30 minutes Note: Enough blotting paper and ninhydrin solution are provided to make 30 sets of “amino acid fingerprints.”
Correlation to Next Generation Science Standards (NGSS)
Science & Engineering Practices
Constructing explanations and designing solutions
Disciplinary Core Ideas
MS-PS1.A: Structure and Properties of Matter MS-PS1.B: Chemical Reactions HS-PS1.A: Structure and Properties of Matter HS-PS1.B: Chemical Reactions HS-LS1.A: Structure and Function HS-LS1.C: Organization for Matter and Energy Flow in Organisms
Crosscutting Concepts
Structure and function Patterns Energy and matter
Performance Expectations
MS-PS1-2: Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.