Fast determination of amphetamine-type stimulants and synthetic cathinones in whole blood samples using protein precipitation and LC-MS/MS

Stimulants are a class of drugs of abuse that act on the central nervous system (CNS) and increase alertness and behavioral excitation. After cannabis, stimulants are the most commonly drug class used globally and accounted for 50 million users in 2018, according to the World Drug Report 2019 published by United Nations Office on Drugs and Crime (UNODC). Amphetamine-type stimulants and synthetic cathinones are the two main classes of synthetic drugs seized in northeast Brazil in recent years. The use of these substances is increasing in popular festivals and raves parties but is also being used in cases of drug-facilitated sexual assault, by truck drivers and others occurrences. The aim of this work was to develop and validate a fast and simple method using protein precipitation extraction and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) to analyze, in a total run time of 7.5 min, eight amphetamine-type stimulants and three synthetic cathinones in whole blood samples. The method has shown LOD ranging from 0.5 to 1.7 ng mL(-1) and LOQ of 5 ng mL(-1) for all the analytes, besides good linearity, precision and accuracy, with no carryover effect observed, while recoveries ranged between 60.2% and 86.2%. The method was applied in the analysis of fifty whole blood samples, collected in cases reported as use of illegal drugs, and is now being implemented for using in routine protocol in the Forensic Toxicology Laboratory of the State of Sergipe, especially considering it proved to be very useful in the investigation of cases of fatal traffic accidents, which is the main demand of forensic toxicology laboratories in Brazil, besides it is possible to increase the number of the analytes which could be included, since new cathinones have appeared frequently on the illicit market.