Desenvolvimento de dispositivos microfluídicos para determinação de cafeína em águas residuárias a partir de ensaios colorimétricos e fluorimétricos
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Data
2018-10-16
Autores
Luchiari, Natália da Costa
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O elevado consumo de produtos que apresentam cafeína em suas composições tem contribuído significativamente para as alarmantes concentrações desse fármaco em esgoto em níveis de concentração que variam de μg L-1 a mg L-1. O desenvolvimento de dispositivos portáteis por prototipagem 3D que em conjunto à reações colorimétricas e fluorimétricas sejam capazes de determinar a presença de cafeína em amostras de águas residuárias é uma proposta inovadora e promissora para análises rápidas e de baixo custo. A técnica de aquisição de imagem usando celular utilizada visando a portabilidade e a acessibilidade do dispositivo miniaturizado, permitiu a digitalização da resposta analítica com auxílio do App OpenCamera. As imagens capturadas foram processadas no software ImageJ para obtenção da intensidade de sinal analítico. Os métodos propostos e de referência (LC-MS/MS e fluorímetro) foram validados segundo diretivas nacionais e internacionais de acreditação e aplicados em amostras de energético, esgoto e medicamentos. O método colorimétrico apresentou linearidade de 100 a 500 mg L-1 de cafeína com LOQ de 100 mg L-1 e LOD de 30,0 mg L-1 para valores de precisão entre 0,0800 e 0,760 %. O efeito de matriz foi avaliado para ambas amostras em água ultrapura e o método foi capaz de determinar cafeína em amostras de medicamentos com precisão. O método fluorimétrico apresentou valores de precisão intradia entre 0,890 e 2,05 % e interdia entre 0,830 e 1,98 % para faixa linear de 100 e 600 mg L-1 de cafeína com LOQ de 100 mg L-1 e LOD de 30,0 mg L-1 e R2 0,900. O efeito de matriz foi inferior a 100% para amostras de energético e esgoto, sendo aplicável a tais matrizes com precisão e exatidão. A faixa de trabalho obtida para ambos os métodos miniaturizados é relativamente ampla, sendo uma importante vantagem analítica para os dispositivos propostos comparados a outros métodos similares descritos na literatura científica. Os dispositivos propostos apresentaram características importantes como custo reduzido, volumes diminutos de reagentes e amostra, análises rápidas, possibilidade de total portabilidade e aplicabilidade em matrizes complexas.
The high consumption of caffeine-containing products in their own compositions has contributed significantly to the alarming concentrations of this drug in wastewater at concentration levels ranging from μg L -1 to mg L -1 . Portable 3D prototyping devices have worked together with colorimetric and fluorimetric reactions being able to determine the presence of caffeine in wastewater samples. It is an innovative and promising option for fast and low cost analyzes. The image acquisition technique has been used smartphones supporting the portability and accessibility in miniaturized devices. OpenCamera App was used to captur images that were processed in the ImageJ software to obtain the analytical signal strength. The proposed and reference methods (LC-MS / MS and fluorimeter) were validated according to the national and international accreditation directives and applied in samples of energy, domestic sewage and medicines. The colorimetric method showed linearity from 100 to 500 mg L -1 of caffeine with LOQ of 100 mg L -1 and LOD of 30.0 mg L -1 for precision values between 0.0800 and 0.760 %. The matrix effect was evaluated for both samples in ultrapure water and the method was able to accurately determine caffeine in drug samples. The fluorimetric method presented values of intraday precision between 0.890 and 2.05 % and between 0.830 and 1.98% for linear range of 100 and 600 mg L -1 of caffeine with LOQ of 100 mg L -1 and LOD of 30.0 mg L -1 and R2 0.900. The matrix effect was less than 100 % for energy and domestic sewage samples, applied to such matrices with precision and accuracy. The working range obtained for both miniaturized methods is relatively broad. It is an important analytical advantage for the proposed devices compared to other similar methods described in the scientific literature. The proposed devices presented important characteristics such as reduced cost, small volumes of reagents and samples, rapid analyzes, possibility of total portability and applicability in complex matrices.
The high consumption of caffeine-containing products in their own compositions has contributed significantly to the alarming concentrations of this drug in wastewater at concentration levels ranging from μg L -1 to mg L -1 . Portable 3D prototyping devices have worked together with colorimetric and fluorimetric reactions being able to determine the presence of caffeine in wastewater samples. It is an innovative and promising option for fast and low cost analyzes. The image acquisition technique has been used smartphones supporting the portability and accessibility in miniaturized devices. OpenCamera App was used to captur images that were processed in the ImageJ software to obtain the analytical signal strength. The proposed and reference methods (LC-MS / MS and fluorimeter) were validated according to the national and international accreditation directives and applied in samples of energy, domestic sewage and medicines. The colorimetric method showed linearity from 100 to 500 mg L -1 of caffeine with LOQ of 100 mg L -1 and LOD of 30.0 mg L -1 for precision values between 0.0800 and 0.760 %. The matrix effect was evaluated for both samples in ultrapure water and the method was able to accurately determine caffeine in drug samples. The fluorimetric method presented values of intraday precision between 0.890 and 2.05 % and between 0.830 and 1.98% for linear range of 100 and 600 mg L -1 of caffeine with LOQ of 100 mg L -1 and LOD of 30.0 mg L -1 and R2 0.900. The matrix effect was less than 100 % for energy and domestic sewage samples, applied to such matrices with precision and accuracy. The working range obtained for both miniaturized methods is relatively broad. It is an important analytical advantage for the proposed devices compared to other similar methods described in the scientific literature. The proposed devices presented important characteristics such as reduced cost, small volumes of reagents and samples, rapid analyzes, possibility of total portability and applicability in complex matrices.
Descrição
Palavras-chave
Cafeína, Colorimétrica, Fluorimétrica, Impressora 3D, Dispositivo