KED (Kinetic Energy Discrimination)
Definition
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 accuracy of Pb, Sb, and Ba measurements against complex swab matrix backgrounds.
- Collision gas
- Helium
- Instrument mode
- ICP-MS collision-reaction cell
- Purpose
- Suppress polyatomic mass interferences
- Application
- GSR analysis of Pb, Sb and Ba
Common questions
How does helium collision gas remove polyatomic interferences?+
Helium atoms collide with ions travelling through the cell; larger, more diffuse polyatomic ions lose more kinetic energy per collision than compact analyte ions, so an energy barrier at the cell exit filters the interferences out while letting the true analyte ions through.
Why is KED especially useful for lead-free GSR analysis?+
Lead-free primers rely on trace elements like Sb, Ba, Sr and Ti at low concentrations, and the swab matrix generates polyatomic species that overlap these masses, so removing that interference is necessary to distinguish genuine gunshot residue from background contamination.
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...
- 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...
- Zinc Peroxide (ZnO2)
- A fuel/oxidiser compound used in some lead-free primer formulations in place of antimony sulphide. Contributes Zn to the GSR particle signature; Zn...