Development and validation of an ultra-performance liquid chromatography-tandem mass spectrometric method for the determination of 25 psychoactive drugs in cerumen and its application to real postmortem samples.

PURPOSE: In the present study, a method for the detection of 25 psychoactive substances in cerumen was developed and validated. This method targets opiates, cocaine, antidepressants, benzodiazepines, antipsychotics and antiparkinsons. METHODS: Analysis was performed on a SCIEX Triple Quad 6500+ system after liquid-liquid extraction. Methanol with 1% acetic acid was chosen as the extraction solvent. After the addition of the solvent, samples were vortexed, sonicated, centrifuged and directly injected into the liquid chromatography-tandem mass spectrometry system. RESULTS: The method was found to be selective and sensitive (limit of detection: 0.017 ng-0.33 ng/mg), the assay was linear for all analytes with linear regression coefficient ranging 0.9911-1.00. The values for intra-assay precision was between 4.34 and 14.6% and inter-assay precision between 5.81 and 17.7%, with accuracy within the acceptable criteria for all analytes. All analytes in cerumen specimens were stable for 48 h at 4 °C and 72 h at - 20 °C, whilst no significant matrix effect or carryover was observed. Applicability was proven by analyzing cerumen samples from 25 deceased with a history of drug abuse. All analytes were detected in real samples, thus confirming the sensitivity of the developed method. CONCLUSIONS: According to our knowledge, it is the first time that a method for the simultaneous detection of 25 psychoactive drugs in cerumen was developed, fully validated and finally applied to 25 postmortem samples.

Determination of fentanyl and norfentanyl in cerumen in the setting of postmortem investigation.

Cerumen is an emerging alternative biological matrix in the field of forensic toxicology. An ultra-high-pressure liquid chromatography-mass spectrometry/mass spectrometry [UHPLC-MS/MS] method for the determination of fentanyl and norfentanyl in cerumen was developed and applied in a mixed drug toxicity fatal case. The method was found to be selective and sensitive (LOQ: 0.05 ng/mg for fentanyl and 0.02 ng/mg for norfentanyl), while validation included recovery, carryover, short-term stability, matrix effect, accuracy, and precision (RSD%). Accuracy ranged from 83.1% to 103.5%, while intra- and inter-day precision ranged from 8.6% to 13.1% and from 8.3% to 15.8%, respectively. Matrix effect experiments showed that matrix did not significantly affect signal intensity (82.3%-96.8%). Short-term stability concerning sample extracts was found satisfactory. Fentanyl and norfentanyl were detected in cerumen at a concentration of 1.17 and 0.36 ng/mg respectively. The findings in cerumen corroborate the cause of death and suggest that cerumen is a potential specimen for detecting drugs of abuse in forensic cases.