Increasing Throughput for Forensic Screening of Raw Case Samples Using the Agilent QuickProbe GC/MS System

Importance of the Topic

Forensic laboratories face increasing pressure to process raw case samples quickly while maintaining data integrity. Traditional workflows involve multiple preparation steps and presumptive tests that extend analysis time. A rapid screening approach that generates reviewable mass spectra without extraction can boost throughput and strengthen evidential value by providing courtroom defensible data at every stage.

Study Objectives and Overview

This study evaluates the performance of the Agilent QuickProbe GC/MS system for direct screening of forensic case samples. Key goals included assessing identification accuracy across diverse matrices, determining sample turnaround time, and establishing a streamlined workflow compatible with ISO 17025 requirements for forensic accreditation.

Instrumentation

• Agilent QuickProbe direct insertion unit (model G3971A) mounted on an Agilent 5977 GC/MS
• Short high-temperature capillary column (Agilent J&W DB-1ht, 1.5 m × 0.25 mm, 0.10 μm) with rapid ramping up to 960 °C/min
• Glass probe and pocket-tip probe holders enabling direct introduction of liquids, solids, powders, and plant materials
• Helium make-up gas flow through open inlet to prevent air intrusion

Methodology and Sample Handling

The workflow required minimal sample preparation. After running system and probe blanks, analysts touched samples with a glass probe for 3–6 seconds, retracted the probe into the holder, and initiated a one-minute chromatographic run. Blanks were run between samples to avoid cross-contamination, with static powders rinsed with water or solvent. Identification was based on mass spectral library matches using American Academy of Forensic Sciences and Cayman Chemical libraries, with a minimum match factor of 80.

Main Results and Discussion

Direct screening yielded chromatographic separation in under one minute and complete screening cycles in three to four minutes, including blanks. Library match scores were excellent for a broad range of compounds. Among already adjudicated case samples, 83 percent were correctly identified. Detected analytes ranged from common drugs such as cocaine, opioids, benzodiazepines, and cannabinoids to emerging substances like synthetic cannabinoids and steroids. Sample throughput increased substantially compared with traditional extraction workflows. The system also provided reviewable mass spectra that satisfy forensic defensibility requirements.

Benefits and Practical Applications

• Elimination of extraction and reagent-based presumptive assays for initial screening
• Rapid turnaround time enabling high-volume case triage
• Generation of reviewable spectral data at each stage, enhancing courtroom defensibility
• Capability to screen for emerging compounds lacking established presumptive tests
• Reduction of analyst workload through division of screening and confirmation tasks and batch processing

Future Trends and Potential Applications

As forensic caseloads continue to grow and compound diversity expands, direct insertion screening is poised for broader adoption. Future developments may include integration with laboratory information management systems, enhanced automation of probe handling, and extensions into quantitative analysis with appropriate calibration protocols. Emerging high-resolution MS could further improve selectivity and sensitivity for novel psychoactive substances.

Conclusion

The Agilent QuickProbe GC/MS system delivers a fast, solvent-free screening workflow capable of generating library-searchable mass spectra without sample preparation. Its implementation in forensic laboratories can dramatically increase throughput, provide defensible data for court, and expand screening capabilities to include a wide range of analytes. This approach supports accreditation requirements and optimizes resource utilization.