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Authors
Abstract(s)
O consumo de drogas de abuso, entre as quais cocaína, existe há muitos anos e
permanece até aos dias de hoje, representando um problema para a saúde pública. A
cocaína (COC) é a segunda droga mais consumida a nível europeu, e por se tratar de
uma substância que estimula o sistema nervoso central (SNC), encontra-se associada a
diversas doenças físicas e mentais. Outro fator preocupante é o impacto na saúde
mental provocado pela pandemia causada pelo coronavírus (covid-19), levando a um
aumento do consumo deste tipo de substâncias. Desta forma, torna-se importante o
desenvolvimento de novas metodologias que permitam detetar e quantificar de forma
fiável estas drogas, podendo utilizar vias indiretas de forma a obter dados credíveis que
indiquem informação sobre o consumo destas substâncias através de amostras de
recolha fácil. Assim sendo, o presente estudo teve como objetivo desenvolver um
método analítico adequado à análise de águas residuais (AR’s), utilizando extração em
fase sólida (SPE) e identificação/quantificação, através da cromatografia gasosa (GC) e
espetrometria de massas em tandem (GC-MS/MS). Os analitos alvo foram COC,
ecgonina metilester (EME), benzoilecgonina (BEG), cocaetileno (COET) e norcocaína
(NCOC). O procedimento de extração previamente otimizado, resultou na aplicação de
50 mL de amostras de efluentes em cartuchos StrataTM-X-C. A extração foi iniciada com
o acondicionamento dos cartuchos com 2 mL de metanol e 2 mL de água
desmineralizada, adição de amostra, seguido de uma lavagem onde foram usados 2 mL
de ácido clorídrico (HCl) (0,1M em água), eluição dos compostos com 2 mL de 5%
hidróxido de amónia em metanol secagem, derivatização e posterior injeção no sistema
GC-MS/MS. A metodologia foi validada seguindo as diretrizes de Scientific Working
group for Forensic Toxicology (SWGTOX). Foi obtida uma linearidade de 0,00625-5
ng/mL para todos os analitos em estudo, com coeficientes de superiores a 0,99 para
todos os compostos. A precisão e exatidão intra- e interdia e intermedia revelaram
coeficientes de variação e BIAS em conformidade com as diretrizes utilizadas. Este
procedimento permitiu recuperações que variaram entre 72-115%. Todos os parâmetros
estudados obedeceram aos critérios definidos. Um dos parâmetros avaliados durante o
desenvolvimento do presente método foi a estabilidade, pois uma das maiores
limitações dos laboratórios de toxicologia reside no armazenamento de amostras antes
e depois do seu processamento, podendo resultar em perdas significativas dos
compostos em estudo. Todos os analitos se mantiveram estáveis nos extratos à
temperatura ambiente durante 24h e nas amostras sujeitas a ciclos de
congelação/descongelação durante 24h. Salienta-se que o método aqui descrito, é o primeiro que utiliza SPE através de
cartuchos StrataTM-X-C, aliada à análise por GC-MS/MS.
Assim, este método constitui uma alternativa adequada para a monitorização da COC e
dos seus metabolitos em amostras de águas residuais, com especial importância quer
no ramo ambiental quer em termos de aplicação forense.
The consumption of drugs of abuse, for instance cocaine, dates many years back and remains until today; therefore, it is a danger to public health. Cocaine (COC) is the second most consumed drug in Europe, and because of the stimulation of the central nervous system (CNS), it has been associated with several physical and mental illnesses. Another concerning factor is the impact on mental health caused by the recent pandemic (covid-19), leading to an increase in the consumption of this type of substance. In this way, it is important to develop new methodologies to detect and quantify these drugs, using indirect ways to obtain credible data, providing information about the consumption of these substances through easy sampling. Therefore, this study aims to develop an analytical method suitable for the analysis of wastewaters (AR’s), using solid phase extraction (SPE) and identification/quantification by gas chromatography-tandem mass spectrometry (GC-MS/MS). The target analytes were cocaine, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET) and norcocaine (NCOC). The previously optimized extraction procedure resulted in the application of 50 mL of effluent into StrataTM-X-C cartridges. The extraction was initiated by conditioning the cartridges with 2 mL of methanol and 2 mL of demineralized water, sample addition, followed by a wash where 2 mL of hydrochloric acid (HCl) (0.1 M in water) was used, elution of the compounds with 2 mL of 5% ammonium hydroxide in methanol drying, derivatization and subsequent injection into the GC-MS/MS system. The methodology was validated following the Scientific Working group for Forensic Toxicology (SWGTOX) guidelines. Linearity was obtained between 0.00625-5 ng/mL for all analytes under study, with coefficients of determination greater than 0.99 for all compounds. Intra- and interday, as well as intermediate, precision and accuracy showed coefficients of variation and BIAS in compliance with the guidelines used. This procedure allowed recoveries ranging from 72-115%. All of the studied parameters met the defined criteria. One of the parameters evaluated during the development of this method was stability, since one of the biggest limitations of toxicology laboratories is storage of samples before and after their processing, which can result in significant losses of the compounds under study. The analytes were stable at room temperature for 24h and in samples subjected to freeze/thaw cycles for 24h.It is important to note that the method described is the first to use SPE using StrataTM-X-C cartridges, combined with GCMS/MS analysis. Thus, this method constitutes a suitable alternative for monitoring COC and its metabolites in wastewater samples, with special importance both in the environmental field and in terms of forensic application.
The consumption of drugs of abuse, for instance cocaine, dates many years back and remains until today; therefore, it is a danger to public health. Cocaine (COC) is the second most consumed drug in Europe, and because of the stimulation of the central nervous system (CNS), it has been associated with several physical and mental illnesses. Another concerning factor is the impact on mental health caused by the recent pandemic (covid-19), leading to an increase in the consumption of this type of substance. In this way, it is important to develop new methodologies to detect and quantify these drugs, using indirect ways to obtain credible data, providing information about the consumption of these substances through easy sampling. Therefore, this study aims to develop an analytical method suitable for the analysis of wastewaters (AR’s), using solid phase extraction (SPE) and identification/quantification by gas chromatography-tandem mass spectrometry (GC-MS/MS). The target analytes were cocaine, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET) and norcocaine (NCOC). The previously optimized extraction procedure resulted in the application of 50 mL of effluent into StrataTM-X-C cartridges. The extraction was initiated by conditioning the cartridges with 2 mL of methanol and 2 mL of demineralized water, sample addition, followed by a wash where 2 mL of hydrochloric acid (HCl) (0.1 M in water) was used, elution of the compounds with 2 mL of 5% ammonium hydroxide in methanol drying, derivatization and subsequent injection into the GC-MS/MS system. The methodology was validated following the Scientific Working group for Forensic Toxicology (SWGTOX) guidelines. Linearity was obtained between 0.00625-5 ng/mL for all analytes under study, with coefficients of determination greater than 0.99 for all compounds. Intra- and interday, as well as intermediate, precision and accuracy showed coefficients of variation and BIAS in compliance with the guidelines used. This procedure allowed recoveries ranging from 72-115%. All of the studied parameters met the defined criteria. One of the parameters evaluated during the development of this method was stability, since one of the biggest limitations of toxicology laboratories is storage of samples before and after their processing, which can result in significant losses of the compounds under study. The analytes were stable at room temperature for 24h and in samples subjected to freeze/thaw cycles for 24h.It is important to note that the method described is the first to use SPE using StrataTM-X-C cartridges, combined with GCMS/MS analysis. Thus, this method constitutes a suitable alternative for monitoring COC and its metabolites in wastewater samples, with special importance both in the environmental field and in terms of forensic application.
Description
Keywords
Águas Residuais Cocaína Metabolitos Spe Stratatm-X-C Gc-Ms/Ms.