Microextraction by packed sorbent (MEPS) for sample preparation in toxicological analyses involving benzodiazepines

Author(s)

Loraine Rezende Togni

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2018-04-17

Examining board members

Marina Franco Maggi Tavares; Karina Helena Morais Cardozo; Álvaro José dos Santos Neto; Maurício Yonamine

• Advisor: Marina Franco Maggi Tavares

Abstract

Microextraction by packed sorbent (MEPS) is a sample preparation technique still little used in toxicology, where the same principles of conventional solid phase extraction are adapted to a miniaturized scale. The main advantages of the technique are associated with the small volume of sample and solvents required, the possibility of performing multiple extractions with the same cartridge and ease process automation. Benzodiazepine drugs are relevant in toxicology because of their widespread use, and effects (which may, for example, compromise the ability to drive vehicles), abuse and records as crime-facilitating drugs. In this work, a MEPS method was developed and optimized for a determination of seven benzodiazepines and their metabolites (diazepam, nordiazepam, clonazepam, flunitrazepam, 7-aminoflunitrazepam, alprazolam, and bromazepam) using 100 µL of post mortem whole blood. After extraction, the eluates were analyzed by reversed-phase liquid chromatography coupled to mass spectrometry. The method was validated according to the recommendations of the Scientific Working Group for Forensic Toxicology, presenting adequate linearity from 5 to 500 ng.mL-1 . The values of accuracy (90.4 to 109.5%), intra-day precision (2.5 to 10.7 %CV) and inter-day (1.1 to 8.0 %CV) also presented satisfactory results. MEPS was performed more than 60 times with the same extractive phase without compromising the results with the evidence of carryover. Institute of Legal Medicine were submitted to analysis by MEPS-LC-MS/MS. In these samples, the following analytes were quantified: diazepam, nordiazepam, clonazepam and bromazepam. The results found in each of the samples were compared with data from the literature. (AU)

• FAPESP's process: 13/06934-5 - Use of the on-line solid phase extraction and of high performance liquid chromatography for the preparation of saliva's and plasma's samples in the emergency toxicological analysis
• Grantee: Loraine Rezende Togni
• Support Opportunities: Scholarships in Brazil - Master