Extraction and simultaneous determination of metoprolol and α-hydroxy metoprolol in latent fingerprints by liquid chromatography tandem mass spectrometry

Abstract

A simple extraction and sensitive simultaneous analysis method for metoprolol and its metabolite alpha-hydroxy metoprolol in latent fingerprint using liquid chromatography-mass spectrometry was developed. The extraction procedure was optimized as scrubbing using cotton swabs for 30 times followed by ultrasonic assistance in 30 °C methanol for 5 min with power of 2000 W. Drug analysis was performed using the mixture of methanol and 0.1% formic acid solution (pH 3.5, 30:70, v/v) as the mobile phase under positive electrospray ionization condition. The linear range obtained was 1.0–500.0 ng/mL for MET, and α-MET, and the limit of detection and the limit of quantification were 0.3 ng/cotton swab and 1.0 ng/cotton swab, respectively. The method showed very slight matrix effect and good recovery to the analytes in the fingermarks. Evaluation of extraction substrates and developing methods showed that the method developed is best used for impermeable substrates and that the commercially development powders have very slight influence on the qualitative detection of metoprolol in fingermarks. Finally, the drug users distinguishing test proved that the method developed for pharmaceuticals could be applied in the forensic analysis for circling out the pool of suspects in the criminal investigation based on their drug use history.