ICP-MS (Inductively Coupled Plasma Mass Spectrometry)
Definition
A bulk elemental quantification technique that dissolves the entire hand swab or SEM stub and measures total element mass per sample. Complements SEM-EDX particle analysis, particularly for aged samples with low particle counts or lead-free primers where particle signatures may be unfamiliar.
- Detection limit
- Sub-ppb (parts per billion) sensitivity
- Sample preparation
- Entire hand swab or SEM stub dissolved into solution for analysis
- Primary use in forensics
- Bulk elemental quantification of gunshot residue, especially with low particle counts or lead-free primers
Common questions
How does ICP-MS differ from SEM-EDS in GSR analysis?+
ICP-MS measures the total elemental mass across an entire hand swab or sample by dissolving it completely. SEM-EDS analyzes individual particles on a stub surface. ICP-MS works best for aged samples with low particle counts or when particle signatures are unfamiliar, making it a useful complement to microscopy-based methods.
What are the advantages of ICP-MS for gunshot residue detection?+
ICP-MS detects elements at sub-ppb sensitivity levels and handles bulk quantification of all elements in a sample at once. This is especially helpful with lead-free primers, where individual particle signatures may not be well-documented in the examiner's reference collection. European forensic labs commonly use it alongside particle analysis.
Can ICP-MS replace particle-based GSR methods like SEM-EDS?+
No. ICP-MS complements rather than replaces SEM-EDS. While ICP-MS gives you total elemental content, SEM-EDS lets you see the morphology and composition of individual particles. Together, they provide both bulk and particulate evidence, which is stronger than either method alone.
Related terms
- AAS (Atomic Absorption Spectrometry)
- An analytical technique measuring the absorption of element-specific wavelengths by atomised sample. For GSR, it quantifies dissolved Pb, Ba and Sb in...
- 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...
- GFAAS (Graphite Furnace AAS)
- An AAS configuration using an electrically heated graphite furnace to atomise the sample, achieving approximately 100-fold lower detection limits than flame AAS....
- 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...
- 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...
- NAA (Neutron Activation Analysis)
- A nuclear analytical technique in which sample irradiation in a research reactor converts stable isotopes to radioactive ones, which are identified by...
- 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,...
- SEM-EDS (ASTM E1588-20)
- Scanning electron microscopy with energy-dispersive X-ray spectroscopy, operated under ASTM E1588-20. The reference method for individual GSR particle detection; provides simultaneous morphological...
- 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...
- 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...
Explained in these topics
- Instrumental GSR Analysis: SEM-EDS, AAS, NAA and Modified GriessA multi-element solution technique that measures elemental masses in a plasma ion source at sub-ppb detection limits. Used as a complement to SEM-EDS in Europe...
- Lead-Free Primer Chemistry and Modern GSR DetectionA bulk elemental quantification technique that dissolves the entire hand swab or SEM stub and measures total element mass per sample. Complements SEM-EDX parti...