Table 2 Various instrumental techniques discussed in the study with their advantages and disadvantages
From: A chronological study of gunshot residue (GSR) detection techniques: a narrative review
Sl No. | Techniques | Advantages | Limitations | Literatures | |
|---|---|---|---|---|---|
1. | SEM/EDS | The method is applied to detect the morphological feature of particle. Along with morphological feature EDX give the elemental analysis too | Cigarette lighter particle are same as GSR in morphology which can cause interference in the study. Not apt for field analysis | Lindsay et al., (Lindsay et al., 2011) | |
2. | Spectroscopic techniques | LIBS | Potential for direct detection LIBS typically samples very small amounts of material (~0.1μg to 1mg) and is therefore practically non-destructive. Simultaneous multi-elemental analysis. | Increased cost and system complexity. Difficulty in obtaining suitable standards (semi-quantitative) Detection limits are generally not as good as established solution techniques. Poor precision—typically 5–10%, depending on the sample homogeneity, sample matrix, and excitation properties of the laser. Possibility of ocular damage by the high-energy laser pulses. | Silva et al., (Silva et al., 2009) |
SERS | Trace elemental analysis 106 times Signal enhancement than Raman spectroscopy | Destructive technique not allowing additional analyses on the sample. The inherent grain-to-grain inhomogeneity of the gunpowders could be a limiting factor to unequivocally link a GSR macro particle with ammunition | López et al., (López-López et al., 2016) | ||
Raman spectroscopy | Highly specific like a chemical fingerprint of a material Portable and hand-held spectrometers that enable for data collection and material detection immediately in the field. | Raman signal are inherently weak Portable or hand held instruments have poorer sensitivity that benchtop instruments. | Buzgar et al., (Buzgar et al., 2009) | ||
IMS | Atmospheric pressure operation No vacuum pumps are required hence simple Overlapping analytes can be separated changing the buffer gas | Not suitable for non-volatile analytes Low proton affinity or ionization potential compounds are hard to detect | Fernandez et al., (Fernández Maestre, 2012) | ||