Leveraging the potential of capsule phase microextraction for simultaneous determination of anaesthetic and opioid drugs in postmortem samples of its fatal intoxication

• Synthesis of microextraction capsule (MEC) using sol-gel CW 20M sorbent. • The method allows high-throughput sample preparation of ∼10–12 samples simultaneously. • Effectively employed for anaesthetic and tramadol analysis in human autopsy samples. • Built-in filtration within MECs negates the necessity for pre-filtration steps. • ComplexMoGAPI and CACI algorithm was used to evaluate greenness and practicality. The reliable identification of anaesthetic and opioid drugs in biological matrices is of critical importance in forensic toxicology, particularly in cases of drug misuse and suspected medical malpractice. Given the typically low concentrations of these analytes in postmortem samples, an efficient extraction and preconcentration strategy is indispensable. Capsule phase microextraction (CPME), a recently developed sol-gel–based sample preparation technology that encapsulates sorbents within a porous tubular polymeric membrane, was employed for the selective isolation of anaesthetics (bupivacaine, lidocaine, ropivacaine, and prilocaine) and the opioid tramadol from postmortem blood and tissue samples (liver, kidney, stomach, and spleen). Subsequent analysis was performed using gas chromatography–mass spectrometry (GC-MS). The optimized CPME-GC-MS method exhibited excellent analytical performance, achieving linear calibration ranges of 0.01-1.0 μg mL⁻¹ in blood and 0.01-1.0 μg g⁻¹ in tissue samples, with limits of quantification as low as 0.0060-0.0079 μg mL⁻¹ (blood) and 0.0080–0.0099 μg g⁻¹ (tissues). Precision studies confirmed strong method reliability, with intra-day repeatability below 5% and inter-day reproducibility below 10%. The method was successfully applied to authentic postmortem specimens from a suspected fatal intoxication case involving anaesthetic and opioid misuse. Beyond its forensic applicability, the environmental and operational sustainability of the protocol was critically evaluated using ComplexMoGAPI, AGREE and CACI assessment tools, confirming the method’s greenness and practicality. Overall, the CPME-GC- MS workflow offers a robust, sensitive, and eco-friendly analytical platform, representing a significant advancement for drug monitoring in medico-legal investigations.