DeHaan Modification
Definition
A refinement of the Griess test procedure for forensic propellant residue detection, using a combined sulphanilic acid + NEDA reagent on filter paper for the contact transfer. Attributed to John DeHaan and widely referenced in US forensic firearms literature.
Related terms
- Azo Dye
- A class of organic dyes containing one or more azo groups (R-N=N-R'). Formed in the Griess test by coupling of a diazonium...
- BSA 2023 (Bharatiya Sakshya Adhiniyam)
- India's evidence statute enacted in 2023, replacing the Indian Evidence Act 1872. Sections 39-46 govern expert testimony, including the admissibility and presentation...
- Contact Wound
- A firearm wound produced when the muzzle is pressed against or within a few centimetres of the target surface. Characterised by a...
- Modified Griess Test
- A contact-transfer colour chemistry test for nitrite-containing propellant combustion residue. Sulphanilic acid undergoes diazotisation with nitrous acid (from NO2 on the target...
- NEDA (N-(1-Naphthyl)ethylenediamine Dihydrochloride)
- The azo coupling component in the modified Griess test. After diazotisation of sulphanilic acid with nitrous acid, NEDA couples with the diazonium...
- NIJ Range Estimation Guidelines
- NIJ Standard 0612.00 (US National Institute of Justice). The primary US guidance document for firing-distance determination methodology, covering test-fire protocols, pattern comparison...
- Sodium Rhodizonate
- A chelating agent producing a scarlet-to-red colour with lead ions at acid pH. Applied to entry-wound margins and garment entry holes to...
- Stippling (Tattooing)
- Discrete punctate abrasions or haemorrhages around an entry wound from individual unburned propellant granules embedding in the epidermis at intermediate range. Unlike...
- Test-Fire Envelope
- The set of reference targets produced by firing the case weapon (or a ballistically equivalent substitute) loaded with the same ammunition at...
Explained in
- Firing Distance Chemistry: Griess Test and Sodium RhodizonateA refinement of the Griess test procedure for forensic propellant residue detection, using a combined sulphanilic acid + NEDA reagent on filter paper for the c...