Application of UHPLC-QqQ-MS/MS Method for Quantification of Beta-Adrenergic Blocking Agents (β-Blockers) in Human Postmortem Specimens

Abstract

Betablockers are one of the most frequently used medications in cardiology. They can lead to fatal drops in blood pressure and heart rhythm disturbances. Death is functional, and poisoning with this group of drugs can be difficult to detect. The liquid-liquid extraction (LLE) method developed using ethyl acetate at pH 9 successfully identified 18 β-blockers in human blood. The method's limit of quantification (LOQ) was in the range of 0.1 to 0.5 ng/mL. No carryover of substances between samples was detected, and no interfering ion current signals were observed in the biological samples at the retention times of the compounds or internal standards. All compounds had a coefficient of determination (R²) above 0.995. Intraday and interday precision (RSD%) and accuracy (RE%) for low and high QC levels were within 1.7-12.3% and -14.4 to 14.1%, respectively. Very good recovery (80.0-119.6%) and matrix effect (±20.0%) values were achieved for all compounds. In addition, fragmentation spectra were collected for all the examined substances, and high-resolution spectra were presented for landiolol and metipranolol, because they are not available in commercial HRMS spectra databases. The developed method was applied in authentic postmortem samples.

Keywords: UHPLC-QqQ-MS/MS; beta-adrenergic receptor antagonists; betablockers; drugs intoxication; forensic toxicology.

Figure 1

(A). Structures of determined compounds. (B). Structures of determined compounds.

Figure 1

(A). Structures of determined compounds. (B). Structures of determined compounds.

Figure 2

Multiple reaction monitoring (MRM) chromatograms of determined β-blockers at a concentration of 50 ng/mL (whole blood matrix).

Figure 3

Multiple reaction monitoring (MRM) chromatograms of determined β-blockers at a concentration of 50 ng/mL (whole blood matrix).

Figure 4

Multiple reaction monitoring (MRM) chromatograms of blank and landiolol at a concentration of 50 ng/mL (whole blood matrix).

Figure 5

Multiple reaction monitoring (MRM) chromatograms of blank and metipranolol at a concentration of 50 ng/mL (whole blood matrix).

Figure 6

Fragmentation spectra (MS/MS) of landiolol achieved with the use of QqQ-MS and QTOF-MS.

Figure 7

Fragmentation spectra (MS/MS) of metipranolol achieved with the use of QqQ-MS and QTOF-MS.

Figure 8

Chromatogram of authentic case sample (Case 2; kidney).