Validation of a non-targeted method devoted to identification and quantitation of toxicologically relevant compounds in plasma with HRMS

Abstract

The objective of this study was to develop and validate a simple method using liquid chromatography hyphenated to high resolution mass spectrometry (HRMS) allowing both the performance of a non-targeted screening and the simultaneous quantification of 29 compounds of interest in clinical and forensic toxicology. Extraction was done with QuEChERS salts and acetonitrile, after addition of internal standard to 200 μL of human plasma samples. The mass spectrometer was an Orbitrap, with a heated electrospray ionization (HESI) probe. The analyses were carried out in full scan experiment with a nominal resolving power of 60,000 FWHM within the 125-650 m/z mass range, followed by four cycles of data dependent analysis (DDA) with a mass resolution of 16,000 FWHM. The untargeted screening was evaluated using 132 compounds, mean limit of identification (LOI) was 8.8 ng/mL (min = 0.05 ng/mL, max = 500 ng/mL) and mean limit of detection (LOD) was 0.25 ng/mL (min = 0.05 ng/mL, max = 5 ng/mL). The method was linear in the 5 to 500 ng/mL range (0.5 to 50 ng/mL for cannabinoids, 6-acetylmorphine and buprenorphine) with correlation coefficients > 0.99, intra- and inter-day accuracy and precision were < 15% for all compounds. The method was successfully applied to 31 routine samples.

Keywords: Forensic toxicology; High resolution mass spectrometry; Orbitrap; Plasma; QuEChERS; Toxicology.