Rapid Analysis of Drugs in Forensic Specimens Using the DPiMS-8060

Importance of the Topic

Drug and toxic substance analysis in forensic organ specimens is challenging due to complex biological matrices, sample degradation, and the need for rapid results.
A direct, minimal-preparation approach can streamline forensic workflows and provide timely detection in critical investigations.

Objectives and Study Overview

This study evaluated the performance of the DPiMS-8060 probe electrospray ionization tandem mass spectrometer for direct analysis of the synthetic narcotic MT-45 in tissue samples.
Qualitative detection, metabolite identification, and quantitative comparison against conventional LC-MS/MS were performed on liver, brain, heart, lung, and kidney specimens.

Used Instrumentation

• DPiMS-8060 mass spectrometer with probe electrospray ionization (PESI) coupled to triple quadrupole MS/MS
• LC-MS/MS system used as a reference method

Methodology

• Sample Preparation: 3 mm tissue sections placed on a sample plate; 35 µL of 10 mM ammonium formate/ethanol solution applied directly, with no further cleanup.
• Qualitative Analysis: Product ion scanning targeting the parent ion [M+H]+ m/z 181 and characteristic fragments (m/z 169, 103, 349) for MT-45 and its mono- and di-hydroxylated metabolites.
• Quantitative Analysis: Standard addition calibration (n=6) using collision energy of 25 V, mass range m/z 50–450, scan speed 405 u/sec, event time 1 sec, and 0.5 min acquisition per sample.
• Comparison: Concentrations obtained with DPiMS-8060 were benchmarked against those from an LC-MS/MS method requiring 20 min per injection.

Main Results and Discussion

• MT-45 was successfully detected in all organs with expected fragment patterns.
• Mono- and di-hydroxylated metabolites were observed in liver extracts, confirming metabolic profiling capability.
• The calibration curve exhibited excellent linearity (R² = 0.9991) and accuracy (relative error within –5.0 % to 9.4 %).
• Quantitative results closely matched LC-MS/MS values (e.g., liver: 4.1 vs. 3.9 µg/mL; lung: 8.7 vs. 10.9 µg/mL), validating the method.
• Analysis time was reduced by 97.5 %, from 20 min to 0.5 min per sample, highlighting significant throughput gains.

Benefits and Practical Applications

• No chromatographic separation or extensive sample cleanup required.
• Comparable accuracy to LC-MS/MS with a fraction of the analysis time.
• Applicable to degraded or challenging organ specimens common in forensic cases.
• Potential for field deployment due to minimal sample handling.

Future Trends and Applications

• Adaptation of ambient ionization techniques to expand analyte coverage.
• Automation of probe sampling and data processing to increase throughput.
• Extension to other forensic targets such as synthetic opioids, designer drugs, and their metabolites.
• Integration into clinical toxicology, environmental monitoring, and point-of-care testing.

Conclusion

The DPiMS-8060 system enables rapid, direct analysis of drugs in organ tissues with minimal pretreatment, achieving both qualitative and quantitative results on par with conventional LC-MS/MS while drastically reducing analysis time.
This method offers a powerful tool for forensic and toxicological investigations requiring high-throughput and reliable detection.

References

Usui, K.; Murata, T., et al. Drug Test Anal. 2018, 10, 1033–1038.