Sherlock X™ Software for Fire Debris Analysis

Significance of the Topic

Fire debris analysis is essential in forensic investigations and fire scene reconstruction. It enables objective detection and characterization of ignitable liquids, supporting legal proceedings with reproducible chemical evidence.

Objectives and Study Overview

This specification describes Sherlock X Software for automated fire debris analysis by GC-MS. Key goals include:

• Automated identification of over 130 hydrocarbon compounds in accordance with ASTM E1618
• Seamless integration with Agilent GC-MS systems and ChemStation software
• Enhanced throughput, standardization, and reduction of manual calibration adjustments

Methodology and Instrumentation Used

Sample preparation follows ASTM E1412 extraction protocols. Calibration employs external standards (NIST SRM 2285 or ASTM E1618-PAK) to ensure accurate compound naming and quantitation. The analytical platform consists of Agilent 6850/6890/7820/7890 gas chromatographs coupled with 5973/5975/5977 mass selective detectors. Software components include Sherlock X with two methods (E1618R and E1618D), Agilent ChemStation Data Analysis D.01 or higher, and Wiley or NIST spectral libraries. Throughput levels are approximately 4 samples per hour for E1618R and 2 samples per hour for E1618D.

Main Results and Discussion

Sherlock X automatically processes each chromatographic run, characterizing major and minor peaks during the GC-MS cool-down cycle without extending run times. It calculates absolute responses and relative percentages for each compound. Visualization tools provide total ion chromatograms (TICs), extracted ion chromatograms (EICs), and quantitative graphical interpretations. A pattern recognition module compares unknown samples against ASTM E1618 compound categories, enabling rapid classification of common ignitable liquids such as gasoline.

Benefits and Practical Applications

• Standardized peak characterization reduces operator variability and manual calibration efforts
• External calibration standards ensure consistent performance across instruments and sample batches
• Automated workflows increase laboratory throughput, meeting high-volume forensic demands
• Objective visualization and categorization tools accelerate result interpretation and reporting

Future Trends and Possibilities

Emerging developments may include expanded compound libraries to cover novel accelerants, machine learning algorithms for improved pattern recognition accuracy, cloud-based data sharing for collaborative case analysis, and integration with high-resolution MS technologies to enhance sensitivity and specificity.

Conclusion

The Sherlock X Software provides a robust, automated solution for fire debris analysis that adheres to ASTM standards, streamlines GC-MS workflows, and delivers reliable identification of ignitable liquids, thereby enhancing forensic laboratory efficiency and data integrity.

References

Specification Sheet: Sherlock X Software for Fire Debris Analysis (MIDI, Inc. 2016)
ASTM E1412 Standard Practice for Ignitable Liquid Residue Analysis
ASTM E1618 Methods for Ignitable Liquid Classification