Forensic examination analysis with IC

Importance of the Topic

Forensic analysis of explosive residues is critical for law enforcement and environmental monitoring. Ion chromatography provides sensitive detection of oxyhalides and related anions at trace levels, supporting criminal investigations and soil and water safety assessments.

Objectives and Study Overview

This study outlines a method for quantifying low concentrations of chlorate, thiosulfate, thiocyanate and perchlorate alongside common anions in explosives and post-blast residues, aiming to deliver robust, high-throughput analyses suitable for forensic laboratories.

Methodology and Instrumentation

Anion separation was achieved on a Metrosep A Supp 4 – 250/4.0 column using a sodium carbonate/bicarbonate gradient. Samples dissolved in 10 % methanol were filtered inline and injected via MiPT. Sequential chemical and CO2 suppression minimized background conductivity. Detection and data processing were performed with a compact suppressed‐conductivity detector and MagIC Net software.
Used instrumentation:

• 930 Compact IC Flex Oven/SeS/Deg
• IC Conductivity Detector
• Metrosep A Supp 4 – 250/4.0 column
• 858 Professional Sample Processor
• MagIC Net 4.0 Professional software

Main Results and Discussion

The method achieved limits of quantification below 1 mg/L for each anion with an RSD of 25 %. Calibration ranges spanned 1–100 mg/L (1–50 mg/L for perchlorate). Resolution exceeded 2.0, blanks remained under 0.1 mg/L, and total run time was shortened to 32 minutes by implementing a flow gradient. Methanol in the sample matrix did not affect analyte separation or detection.

Practical Benefits and Applications

This approach offers a rapid, reliable workflow for trace analysis in forensic, environmental, and security contexts. Its compatibility with compact IC systems enables decentralized testing, while integration with professional multi-channel systems supports comprehensive anion and cation profiling.

Future Trends and Opportunities

• Coupling ion chromatography with mass spectrometry for definitive identification
• Enhanced automation and high-throughput screening
• Development of faster suppression and elution strategies
• Application of chemometric and AI tools for forensic fingerprinting
• Expansion to environmental in situ monitoring

Conclusion

The presented IC method delivers fast, sensitive, and robust detection of key anionic residues in explosives. Its abbreviated run time and low detection limits make it a valuable asset for forensic and environmental laboratories. Integration with advanced IC-MS workflows offers further specificity and confirmation.

References

1. Dicinoski et al. (2006), Analytical Letters 39(4), 639–657
2. Barron et al. (2014), Analytica Chimica Acta 806, 27–54