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Abstract(s)
A venlafaxina (VEN) é um fármaco antidepressivo, sendo este um composto recorrentemente usado nos tempos atuais. Contudo a sua presença no meio ambiente faz com seja considerado um poluente emergente não havendo monitorização e/ou regulação dos seus níveis no ambiente, podendo assim afetar os ecossistemas aquáticos e consequentemente a saúde humana. Por isso, é fundamental o desenvolvimento de sistemas analíticos eficazes para este tipo de poluentes. Assim, o objetivo do presente trabalho foi o desenvolvimento de um sensor eletroquímico baseado em papel fibra de carbono (CPS) simples para determinação de VEN. Inicialmente, foi caracterizado o comportamento eletroquímico deste fármaco por voltametria cíclica, tendo-se verificado que apresenta um pico de oxidação a cerca de 1 V (Ag/AgCl, KCl 3 M). Para uma determinação mais sensível, foi usada a técnica de voltametria de onda quadrada, procedendose
à otimização das condições analíticas. Especificamente, obteve-se um pH ótimo de 9 procedendo-se em seguida à otimização da amplitude, frequência e degrau de potencial, obtendo-se valores ótimos correspondentes a 0,06 V, 100 Hz e 0,0175 V, respetivamente. Por fim otimizou-se a deposição de analito à superfície do CPS, obtendo-se um potencial de deposição de 0,2 V e um tempo de deposição de 60 s. Depois de otimizadas as condições analíticas procedeu-se à realização da curva de calibração, obtendo-se 2 zonas lineares, de 0,2 a 2 uM e de 3 a 10 uM. O CPS apresentou um limite de deteção de 0,28 uM e um limite de
quantificação de 0,86 uM. O CPS foi posteriormente validado numa amostra real, de água da torneira recolhida no laboratório, onde se obteve uma recuperação de 71% pelo método de adição padrão o que indica que melhorias ainda podem ser implementadas para aumentar o desempenho do sensor desenvolvido. Conclui-se, assim, que este sensor baseado em CPS tem grandes potencialidades de ser aplicado em análises ambientais devido à sua eficiência eletroquímica, capacidade de miniaturização e portabilidade, assim como pela sua sustentabilidade.
Venlafaxine (VEN) is an antidepressant drug, which is frequently used today. However, its presence in the environment has been considered an emerging pollutant, since there is no monitoring and/or regulation of its levels in the environment, thus potentially affecting aquatic ecosystems and consequently human health. Therefore, it is essential to develop effective analytical systems for this type of pollutants. Thus, the objective of the present work was the development of a simple electrochemical sensor based on carbon fiber paper (CPS) for determining VEN. Initially, studies of the electrochemical behavior of this drug were carried out using cyclic voltammetry, and it was found that it presents an oxidation peak at around 1 V (Ag/AgCl, KCl 3 M). For a more sensitive determination of VEN, the SWV technique was used, optimizing the analytical conditions. Specifically, an optimal pH of 9 was obtained, followed by the amplitude, frequency and potential step, obtaining optimal values corresponding to 0.06 V, 100 Hz and 0. 0175 V, respectively. Finally, the deposition of analyte on the CPS surface was optimized, obtaining a deposition potential of 0.2 V and a deposition time of 60 s. After optimizing the analytical conditions, the calibration curve was carried out, obtaining 2 linear zones, from 0.2 to 2 uM and from 3 to 10 uM. The CPS had a limit of detection of 0.28 uM and a limit of quantification of 0.86 uM. The CPS was subsequently validated on a real sample of tap water collected in the laboratory, where a recovery of 71% was obtained using the standard addition method, which indicates that improvements can still be implemented in order to improve the performance of this sensor.
Venlafaxine (VEN) is an antidepressant drug, which is frequently used today. However, its presence in the environment has been considered an emerging pollutant, since there is no monitoring and/or regulation of its levels in the environment, thus potentially affecting aquatic ecosystems and consequently human health. Therefore, it is essential to develop effective analytical systems for this type of pollutants. Thus, the objective of the present work was the development of a simple electrochemical sensor based on carbon fiber paper (CPS) for determining VEN. Initially, studies of the electrochemical behavior of this drug were carried out using cyclic voltammetry, and it was found that it presents an oxidation peak at around 1 V (Ag/AgCl, KCl 3 M). For a more sensitive determination of VEN, the SWV technique was used, optimizing the analytical conditions. Specifically, an optimal pH of 9 was obtained, followed by the amplitude, frequency and potential step, obtaining optimal values corresponding to 0.06 V, 100 Hz and 0. 0175 V, respectively. Finally, the deposition of analyte on the CPS surface was optimized, obtaining a deposition potential of 0.2 V and a deposition time of 60 s. After optimizing the analytical conditions, the calibration curve was carried out, obtaining 2 linear zones, from 0.2 to 2 uM and from 3 to 10 uM. The CPS had a limit of detection of 0.28 uM and a limit of quantification of 0.86 uM. The CPS was subsequently validated on a real sample of tap water collected in the laboratory, where a recovery of 71% was obtained using the standard addition method, which indicates that improvements can still be implemented in order to improve the performance of this sensor.
Description
Keywords
Electrochemical sensor Venlafaxine Carbon fiber paper Voltammetry Emerging pollutants Sensor eletroquímico Venlafaxina Papel fibra de carbono Voltametria Poluentes emergentes