Zinc Peroxide (ZnO2)
Definition
A fuel/oxidiser compound used in some lead-free primer formulations in place of antimony sulphide. Contributes Zn to the GSR particle signature; Zn is also present at higher background levels in many environmental sources, reducing analytical specificity relative to Sb.
- Role
- Fuel/oxidiser in some lead-free primer mixes
- Replaces
- Antimony sulphide (Sb2S3) in traditional primers
- GSR marker
- Zn
- Specificity issue
- Zn has high environmental background compared to Sb
Common questions
Why is zinc a weaker GSR indicator than antimony?+
Zinc appears widely in brake dust, fertilisers, galvanised metal and other everyday sources, so finding Zn particles alone does not point specifically to firearm discharge the way Sb, Ba and Pb combinations traditionally did.
How do examiners compensate for lead-free primer chemistry?+
SEM-EDX analysis is shifted toward morphology plus multi-element correlation (Zn with other primer-specific elements and particle shape) rather than relying on any single element as a diagnostic marker.
Related terms
- Diazol / SINOXIDE
- A diazonium salt-based organic initiating compound used in Sintox and related lead-free primer formulations, replacing lead styphnate. Does not contribute Pb, Sb,...
- ENFSI EWG-GSR Best Practice Manual
- Published in 2016 by the European Network of Forensic Science Institutes Expert Working Group on Gunshot Residue. The primary guidance document for...
- ICP-MS (Inductively Coupled Plasma Mass Spectrometry)
- A bulk elemental quantification technique that dissolves the entire hand swab or SEM stub and measures total element mass per sample. Complements...
- KED (Kinetic Energy Discrimination)
- An ICP-MS collision-reaction cell mode using helium gas to reduce polyatomic interferences on analyte masses. Used in GSR ICP-MS analysis to improve...
- NIST SRM 2710A / 2711A
- Montana Soil certified reference materials (CRMs) with certified concentrations of Pb, Sb, Ba, and many other elements. Used to calibrate and quality-control...
- Non-Toxic Ammunition (NTA)
- A broad product category encompassing any small-arms ammunition with lead-free primers and, often, lead-free projectile materials. Includes lines from Federal Premium, CCI,...
- SINTOX
- A lead-free, heavy-metal-free primer formulation developed by DAG (Deutsche Ammunitions- und Geschossfabrik) and Geco in Germany in the 1990s-2000s, replacing lead styphnate...
- Strontium Peroxide (SrO2)
- An initiating compound used in some lead-free primer formulations, particularly in Norma Sintox cartridges. Contributes Sr to the GSR particle signature. Sr...