Forensic Toxicological Analysis of Atenolol in Postmortem Femoral Blood and Liver Tissue Using LC-MS/MS: First Evidence of Atenolol Fatality

Atenolol is a selective 1 blocker used in the treatment of hypertension and dysrhythmias.We developed a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the detection and quantification of atenolol in blood and liver tissue from a fatal atenolol overdose case.Sample cleanup was performed using a C 18 solid phase extraction (SPE) cartridge, and separation was achieved on a Kinetex C 18 column.Atenolol identification was performed using LC-MS/ MS with electrospray ionization in positive ion mode.The method was validated for linearity, precision and accuracy.In blood, the matrix effect and recovery of atenolol were 109.9% and 83.6%, respectively; in liver tissue, they were 105.7% and 83.4%, respectively.The method demonstrated good accuracy (92.4-99.2% in blood and 87.8-103.5% in liver tissue), precision (2.7-9.0% in blood and 3.2-10.7% in liver tissue), and linearity (0.02-2.0 mg/L in blood and 0.25-20.0mg/kg in liver tissue).The limits of detection (LOD) of atenolol were 0.005 mg/L in blood and 0.05 mg/kg in liver tissue.This method was applied to authentic samples from two fatal atenolol overdose cases: the first showed a femoral blood atenolol concentration of 10.86 mg/L (Case 1), and the second showed a liver tissue concentration of 106.9 mg/kg (Case 2).While Case 1 demonstrated a lethal blood concentration exceeding previously reported toxic levels, Case 2 revealed unprecedented hepatic accumulation of atenolol, underscoring the importance of both matrices in forensic interpretation.This study provides the first forensic evidence that fatal cardiovascular toxicity can be attributed to atenolol overdose alone, validated through detailed blood and liver concentration analysis using LC-MS/MS.