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Quantitation using GC-TOF-MS: example of bromazepam
B Aebi1, R Sturny-Jungo, W Bernhard
1Forensic Chemistry and Toxicology, Institute of Legal Medicine, University of Berne, Bühlstrasse 20, CH-3012 Berne, Switzerland. beat.aebi@irm.unibe.ch
Forensic Science International
|September 5, 2002
Summary
Time-of-flight mass spectrometry (TOF-MS) provides enhanced capabilities for forensic toxicology. GC-TOF-MS demonstrated superior sensitivity and selectivity in analyzing benzodiazepines compared to other methods, proving valuable in real forensic cases.
Area of Science:
- Analytical Chemistry
- Forensic Science
- Toxicology
Background:
- Forensic toxicology requires sensitive and selective analytical methods for drug detection.
- Traditional methods like gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-diode array detection (HPLC-DAD) face challenges with complex matrices and low concentrations.
- Time-of-flight mass spectrometry (TOF-MS) presents a potential advancement in this field.
Purpose of the Study:
- To evaluate the performance of gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) for the qualitative and quantitative analysis of benzodiazepines in forensic toxicology.
- To compare GC-TOF-MS with other established techniques, including quadrupole GC-MS, gas chromatography-electron capture detection (GC-ECD), and HPLC-DAD.
- To assess the applicability of GC-TOF-MS in real forensic cases involving bromazepam.
Main Methods:
- Qualitative and quantitative analyses of diazepam, nordazepam, and bromazepam were performed using GC-TOF-MS.
- Method validation parameters such as limit of detection (LOD), limit of quantitation (LOQ), and signal-to-noise ratios (S/N) were assessed for GC-TOF-MS.
- Comparative analyses were conducted using quadrupole GC-MS, GC-ECD, and HPLC-DAD.
- Calibration curves for bromazepam in human blood were generated using GC-TOF-MS, GC-ECD, and HPLC-DAD, with medazepam as an internal standard.
Main Results:
- GC-TOF-MS demonstrated high sensitivity and selectivity, reflected in its method validation parameters.
- Correlation coefficients for bromazepam calibration were consistently high (≥0.99) across GC-TOF-MS, GC-ECD, and HPLC-DAD.
- Quadrupole GC-MS in full scan mode lacked sufficient sensitivity for extracted sample comparison.
- In two real forensic cases, GC-TOF-MS successfully identified or quantified bromazepam, whereas HPLC-DAD and GC-ECD yielded inconclusive results due to interfering background signals.
Conclusions:
- GC-TOF-MS offers significant advantages in sensitivity and selectivity for forensic toxicology applications.
- The technique proved effective in overcoming matrix interferences that challenged other analytical methods.
- GC-TOF-MS is a promising analytical tool for the accurate detection and quantification of drugs in forensic investigations.
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