Detection of Cocaine and Metabolites in Bone Following Decomposition Using 2D LC-MS-MS

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Biomolecular Analysis

Background:

• Quantification of cocaine and metabolites in decomposed postmortem samples presents challenges in forensic toxicology.
• Bone offers a viable alternative matrix for drug analysis when other specimens are unavailable.
• Current drug detection methods in complex matrices like bone are often time-consuming.

Purpose of the Study:

• To develop a robust extraction and clean-up methodology for cocaine and its metabolites in bone.
• To achieve target limits of detection using multidimensional chromatography.
• To reduce sample preparation time for forensic analysis.

Main Methods:

• Rat specimens underwent chronic cocaine self-administration followed by decomposition in an outdoor facility for 12 months.
• Homogenized bone samples were extracted using a mixed-mode reversed-phase/ion exchange sorbent.
• Analysis was performed using 2D liquid chromatography-mass spectrometry-mass spectrometry (LC-MS/MS) with direct eluent injection.

Main Results:

• The limit of quantitation (LOQ) for cocaine and benzoylecgonine was 0.05 ng/g.
• The LOQ for ecgonine methyl ester was 0.1 ng/g.
• The analytical method demonstrated a linear dynamic range of 0.05-10 ng/g for cocaine with R² = 0.998.

Conclusions:

• The developed microextraction protocol combined with multidimensional chromatography significantly decreases sample preparation time.
• This method maintains analytical quality comparable to existing single-dimension chromatography techniques.
• The study provides an efficient approach for cocaine and metabolite analysis in bone for forensic applications.