Percorrer por autor "Maria, Marisa H."
A mostrar 1 - 4 de 4
Resultados por página
Opções de ordenação
- Determination of dextromethorphan and dextrorphan in urine using bar adsorptive microextraction followed by gas chromatography : mass spectrometry analysisPublication . Maria, Marisa H.; Fonseca, Margarida; Quintas, Alexandre; Neng, Nuno R.Over the past few years, the misuse of medications has progressively increased, posing a significant public health concern. This study proposed the development and validation of an alternative and greener analytical method for the determination of dextromethorphan (DXM) and its major metabolite, dextrorphan (DXO), in urine matrices using bar adsorptive microextraction (BAμE), followed by gas chromatography–mass spectrometry (GC-MS) analysis. Under optimized experimental conditions, average recoveries of 96.3% and 80.4% were achieved for DXM and DXO, respectively. The analytical limits obtained were 0.016 μg/mL for the limit of detection and 0.054 μg/mL for the limit of quantification. The working range was from 0.06 μg/mL to 2.0 μg/mL, with linearity for both compounds by determination coefficients (r2 > 0.99) and the goodness-of-fit and lack-of-fit tests. Intra-day precision and trueness yielded values below 8.77% and 16.28%, respectively, for both compounds. Inter-day precision and trueness values were below 7.67% and 9.73%, respectively. The application to 26 urine samples allowed the quantification of both compounds, with concentrations ranging from 0.06 to 3.21 μg/mL for DXM and 0.06 to 8.88 μg/mL for DXO. The method proved to be effective, selective, sensitive, simple, and cost-effective in the detection and quantification of DXM and DXO, reinforcing its applicability and feasibility in various laboratory contexts.
- 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
- Simultaneous determination of three phosphatidylethanol homologues, 12 drugs and metabolites in whole blood by LC–MS/MSPublication . Maria, Marisa H.; Neng, Nuno R.; Berg, ThomasThe use of alcohol, legal and illicit substances poses great negative consequences on health and economy worldwide. LC-MS/MS allow simultaneous determination of multiple compounds in biological matrices. The aim of this study was to develop a LC-MS/MS method for the determination of the alcohol biomarker phosphatidylethanol (PEth) – including three homologues (PEth 16:0/18:1, PEth 16:0/18:2, PEth 18:0/18:1) - cocaine and three metabolites, and 8 other drugs in whole blood. Whole blood in K2EDTA tubes was prepared by liquid-liquid extraction using heptane/ethyl acetate/2-propanol (16:64:20, v:v:v). Chromatographic separation was achieved on an Acquity BEH C18 column (50 × 2.1 mm I.D., 1.7 µm particles). Mobile phase was 0.025 % ammonia, pH 10.7 (Solvent A) and methanol (Solvent B). The method was fully validated with isotope-labelled internal standards for 10 compounds. Inter-assay precision and accuracy were within ± 16 % for all analytes at five to seven tested concentrations. Recovery was within 42–79 % for 14 compounds and 11 % for benzoylecgonine. Matrix effects were within ± 25 % for most analytes. Internal standards compensated for matrix effects for compounds that had their own internal standards. A robust, precise, and accurate LC-MS/MS method for the determinations of three PEth homologues and 12 drugs and metabolites was, developed and validated. The method is valuable, especially for detecting polydrug use and alcohol consumption. To the best of our knowledge, this is the first LC-MS/MS method for the simultaneous determination of three PEth homologues and different drugs and metabolites.
- Sorbent strip microextraction as a practical tool for drug screening : application to opioids and local anesthetics in human urinePublication . Maria, Marisa H.; Berg, Thomas; Neng, Nuno R.The present contribution proposes a new design for adsorptive microextraction devices that promote a user-friendly and greener analytical approach. Novel Sorbent Strip Microextraction (SSμE) devices were made using a flexible adhesive film coated with convenient sorbents. Comparing the previous adsorptive microextraction devices, i.e., bar adsorptive microextraction and multi-sphere adsorptive microextraction, the main advantage of the sorbent strip device is its simple design and reduced device preparation time and waste. To demonstrate its applicability, three opioids (buprenorphine, tapentadol, and tramadol) and two local anesthetics (articaine and bupivacaine) were used as model compounds in urine matrices, followed by high-performance liquid chromatography with diode array detector (HPLC-DAD) analysis. Key parameters such as sorbent type, desorption conditions, and microextraction variables were systematically optimized by experimental designs. Under the final conditions, the method achieved recoveries ranging from 78% to 108%, trueness within ±7% and precision expressed by relative standard deviation below 13%. The technique demonstrated good linearity (r2 ≥ 0.9922) across dynamic ranges of 5–500 ng/mL for local anesthetics and 50–5000 ng/mL for opioids. The validated SSμE/HPLC-DAD methodology was successfully applied to real urine samples, confirming its high precision and accuracy. The proposed microextraction technique offers a practical, eco-friendly, and effective alternative for routine drug screening in complex biological matrices and presents significant advantages over traditional and other microextraction-based methods.