- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- Introduction
- Objectives
- AFTE Knowledge and Ability Factors
- Powders and Residues
- Examination
- Distance Determination
- Significance of Results
- Contact Shot
- Nitrite Residues
- Vaporous Lead Residues
- Residues Consistent with the Passage of a Bullet
- Residues Consistent with the Discharge of a Firearm
- Interpretation Challenges
- Reproduction of Results
- Nitrite Residue Patterns
- Shot Patterning
- Chemical Testing
- Shot Pattern Reproduction
- Selected Bibliography
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Chemistry
Home > Gunshot Residue and Distance Determination > Examination > Chemical Testing > Chemistry
An ammonium hydroxide lift of a ricochet
mark sprayed with DTO reagent
The Dithiooxamide Test was published in Fritz Fiegl’s Spot Tests in Inorganic Analysis as a test for the detection of the presence of various metals. The color produced by the test would indicate the particular metal present.
The chemistry of the Dithiooxamide Test is comprised of the following process:
- Material from the perimeter of a suspected bullet hole is exposed to an ammonia solution.
- The same material is exposed to a solution of dithiooxamide dissolved in ethanol. If cuprous material is present, a copper complex with a characteristic color forms.
- A dark gray-green color indicates the presence of copper-bearing material in bullet wipe.
- A blue-pink color indicates the presence of nickel (e.g., silver-tipped bullets).
