Percorrer por autor "Pereira, Joana R. P."
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- Bar adsorptive microextraction approach for trace determination of local anesthetics in urine matricesPublication . Pereira, Joana R. P.; Rocha, Daniela C.; Neng, Nuno R.; Maurício, Paulo; Torres, M. Edite; Ahmad, Samir M.; Quintas, AlexandreThe present work reports the development, optimization, and validation, of a methodology to determine lidocaine, procaine, tetracaine, and benzocaine in urine matrices. Two extractive preconcentration techniques, solid-phase microextraction (SPME) LC Tips and bar adsorptive microextraction (BAμE), were studied and applied to the four target anesthetics, followed by gas chromatography-mass spectrometry (GC-MS) analysis. Several parameters that could affect microextraction and back-extraction were optimized using two different designs of experiments (Box–Behnken and full-factorial) to maximize extraction efficiency from aqueous media. Under optimized experimental conditions, the BAμE technique showed better performance than SPME LC Tips and was chosen for validation assays and urine sample analysis. In blank urine, the BAµE/GC-MS methodology revealed suitable sensitivity (LOD between 2 and 18 ng/mL), good linearity (r2 ≥ 0.9945) between 0.5 and 30.0 µg/mL and recovery yields of 30.3–97.9%. Good precision (%RSD ≤ 8.8%) and accuracy (bias % between −15.9 and 15.0%) values were achieved. The developed methodology was successfully applied to the target anesthetics analysis of volunteers’ urine matrices and proved to be an environmentally friendly alternative to monitor trace levels of local anesthetics in complex matrices compared to other extraction techniques.
- Collaborative harm reduction efforts lead to the first detection of 5-cyano isotodesnitazene in illicit street drugsPublication . Barra, Bárbara F. C.; Pereira, Joana R. P.; Ferreira, Daniela R.; Oeri, Hans; Martins, Daniel; Almeida, Rui M.; Oatley, Giles; Neng, Nuno R.; Gaspar, Helena; Quintas, AlexandreIn the ongoing opioid crisis, regulatory restrictions on fentanyl and its derivatives have led to the emergence of nitazenes, a class of highly potent synthetic opioids synthesised during the 1950s but never approved for medical use. Structurally distinct from traditional opioids, nitazenes have gained increasing presence in illicit drug markets since 2019, contributing to a growing number of drug-related deaths across Europe, North America, and Australia. The rapid proliferation of novel nitazene analogues presents a significant challenge to law enforcement and public health systems. Drug-checking services (DCS) are currently one of the most effective tool for early detection and response, enabling real-time surveillance and consequently reducing the impact of overdoses due to Novel Synthetic Opioids. As a complement, universities can provide the scientific expertise and infrastructure necessary to confirm molecules detected by DCS. This study is the first report identifying and confirming 5-cyano isotodesnitazene in a street-sold drug, through an international collaboration involving two DCSs and three academic institutions. The structural elucidation was achieved through complementary analytical techniques comprising gas chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The present work highlights the essential role that cross-sector cooperation and analytical innovation play in tackling the rapidly evolving threat of novel synthetic opioids.
- Development and validation of a simple and fast method for routine analysis of new synthetic opioids and hallucinogens in whole blood using protein precipitation and UHPLC-MS/MSPublication . Pereira, Joana R. P.; Antunes, Mónica; Neng, Nuno R.; Mustra, Carla; Franco, João; Fonseca, SuzanaIn forensic toxicology, the rapid and reliable detection of emerging synthetic opioids and hallucinogens is crucial for case investigations and public health monitoring. This work describes the development, optimization and validation of a simple, fast and sensitive methodology for the simultaneous analysis of 6 new synthetic opioids (carfentanil, fentanyl, isotonitazene, metonitazene, norfentanyl, and sufentanil) and 2 hallucinogens (lysergide [LSD] and mescaline), together with the main LSD metabolite 2-oxo-3-hydroxy-lysergide [LSD-OH], in whole blood samples by liquid chromatography coupled to tandem mass spectrometry. Under optimized experimental conditions, linearity was verified between 0.1 and 20 ng/mL for all analytes except mescaline (2.5–500 ng/mL), with r2 > 0.99 for 1/x weighting, and no significant carryover or matrix effects were observed. Good precision (% RSD < 13 %) and trueness (% Bias within ± 20 %) values were achieved. The estimated limit of quantification (LOQ) was 0.1 ng/mL for all compounds except mescaline (2.5 ng/mL). Authentic forensic samples were also analyzed, and positive samples for fentanyl, norfentanyl, and sufentanil were identified. The proposed methodology allows the simultaneous analysis of compounds from different families of psychoactive substances, in both postmortem and in vivo samples, using only 50 µL of whole blood. The demonstrated speed, simplicity, and effectiveness make it particularly advantageous for routine implementation in forensic toxicology laboratories.
- Nitazenes : the emergence of a potent synthetic opioid threatPublication . Pereira, Joana R. P.; Quintas, Alexandre; Neng, Nuno R.The global unregulated drug supply faces a critical challenge with the emergence of nitazenes, a class of novel synthetic opioids (NSOs) structurally distinct from fentanyl and associated with extreme potency and high risk of fatal overdose. First synthesised in the late 1950s, etonitazene was a target of preclinical research in rats and rhesus monkeys, but it never reached clinical trials due to an unfavourable balance between therapeutic and toxic effects. Nitazenes’ consistent reappearance began in 2019 with isotonitazene, followed by a rapid proliferation of analogues worldwide, many reported to be hundreds to thousands of times more potent than morphine and, in some cases, stronger than fentanyl. This rise is fuelled by their ease of synthesis, low production costs, and evasion of regulatory controls. Nitazenes are frequently mis-sold as counterfeit medications or adulterated into other drugs, resulting in unintentional exposure and overdose, particularly among opioid-naïve users. The primary cause of death is severe and prolonged respiratory depression. Analytical challenges are significant, as traditional screening methods are ineffective, and the low concentration in biological samples requires expensive and highly sensitive liquid chromatography mass spectrometry techniques. This perspective paper highlights critical gaps in detection, clinical management, and regulatory readiness for nitazenes. Urgent efforts are needed to improve surveillance, develop robust analytical methodologies, provide clinical guidance to nitazene intoxications, and strengthen international policy to curb their proliferation.
- Novas abordagens verdes para determinação de anestésicos locais em matrizes biológicasPublication . Pereira, Joana R. P.; Rocha, Daniela C.; Neng, Nuno R.; Ahmad, Samir Marcos; Torres, M. Edite; Quintas, AlexandrePoster apresentado nas IV Jornadas Científicas Egas Moniz. Monte de Caparica, 27-30 novembro de 2023
- SENTINEL : tackling dangerous nitazene opioidsPublication . Maria, Marisa H.; Pereira, Joana R. P.; Ferreira, Daniela R.; Barra, Bárbara F. C.; Antunes, Alexandra M. M.; Família, Carlos; Oliveira-Torres, Edite; Justino, Gonçalo C.; Gaspar, Helena; Couceiro, Joana; Caldeira, Maria; Serra, Patrícia A.; Almeida, Rui M.; Fonseca, Suzana; Silva, Zoé E. Vaz da; Quintas, Alexandre; Neng, Nuno R.Poster apresentado nas VI Jornadas Científicas Universitárias e Politécnicas Egas Moniz. Monte de Caparica, 24 a 28 de novembro 2025