Rapid Forensic Toxicology Screening Using an Agilent 7890A/NPD/5975C/DRSGC/MSD System

Importance of the Topic

The rapid and reliable screening of forensic toxicology samples is critical in judicial and investigative contexts. High sample throughput and the ability to analyze complex biological matrices demand workflows that combine speed, sensitivity, and reliable compound identification.

Study Objectives and Overview

This application brief by Bruce Quimby describes an optimized GC/MSD system capable of simultaneous scan, SIM, and nitrogen-phosphorus detection in a single, accelerated run. The goal is to screen whole blood extracts for up to 278 target compounds in less than 9 minutes per sample while maintaining data quality and interpretability.

Methodology and Instrumentation

• Gas Chromatograph: Agilent 7890A with High Speed Oven Accessory, DB-17 ms column, constant pressure splitless injection, helium carrier gas, solvent venting and backflush capability.
• Mass Spectrometer: Agilent 5975C MSD operating in simultaneous full-scan (42–550 amu) and SIM modes.
• Detector: Capillary Nitrogen-Phosphorus Detector (NPD) with hydrogen, air, and nitrogen makeup flows for selective nitrogen response.
• Software: Deconvolution Reporting Software (DRS) and AMDIS library for automated deconvolution and compound identification.

Main Results and Discussion

The 2× accelerated method reduced the GC/MSD cycle time from 17 min to 8.5 min, delivering over 85% time savings compared to separate acquisitions. All analytes detected by the conventional 1× method were identified in the shorter run. SIM provided a 10-fold improvement in signal-to-noise for low-level fentanyl compared to scan mode. Backflushing efficiently removed late-eluting matrix interferences, reducing ghost peaks and extending detector lifespan.

Benefits and Practical Applications

• Single-run acquisition of scan, SIM, and NPD signals minimizes instrument downtime and sample queuing.
• DRS facilitates rapid interpretation of coeluting peaks in complex matrices.
• Backflush strategy limits contamination and reduces maintenance frequency.
• Enhanced detection of trace-level compounds supports forensic casework and toxicology screening.

Future Trends and Potential Applications

Ongoing advancements may integrate automated sample preparation, expanded target libraries, and machine-learning-driven data analysis. Such innovations have the potential to further streamline forensic workflows, increase analyte coverage, and enable real-time decision support in toxicology laboratories.

Conclusion

The combined use of high-speed GC/MSD with simultaneous detection modes and DRS delivers substantial reductions in analysis time and simplifies data processing without sacrificing sensitivity or compound coverage. This approach offers a robust solution for high-throughput forensic toxicology screening.

Reference

Quimby B. Rapid forensic toxicology screening using an Agilent 7890A/NPD/5975C/DRS GC/MSD system. Application Brief. Agilent Technologies; 2007.