- 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
Modified Griess Test
Home > Gunshot Residue and Distance Determination > Examination > Chemical Testing > Modified Griess Test
The Modified Griess Test is a chemically specific chromophoric (color-producing) test for the presence of nitrite compounds, such as those produced by the burning of smokeless powder. This test focuses on the analysis of the size and density of patterns of nitrite residues on a victim’s clothing or other objects as well as their reproduction at known distances using the suspect’s firearm in combination with the same type of ammunition.
This test has superseded the original Griess Test in that it does not involve the use of Marshall’s Reagent, a solution suspected of being a carcinogen. Essentially, the new test avoids the use of N-(1-naphthyl)-ethylenediamine dihydrochloride, a component of Marshall’s Reagent. This modification is safer, provides more vivid color results, and uses less expensive reagents and test media than the original Griess Test.
Click here for additional information on the evolution of the Modified Griess Test
It is important to keep in mind that the Modified Griess Test does not yield a positive result for nitrate compounds, such as completely unburned smokeless powder particles. When smokeless powder burns or partially burns, nitrite compounds are formed, which may be detected by the use of the Modified Griess Test.
