Desenvolvimento de um dispositivo microfluídico a base de papel empregando um sensor RGB

Abstract

Colorimetric analyses are chemical analysis techniques that use the color and variation of a solution to determine the concentration of a specific chemical species. These analyses can be performed using different types of equipment, such as spectrophotometers and microfluidic devices, and are widely used in various fields, such as medicine, the food industry, and environmental chemistry. The present study was based on the development of a paper-based microfluidic device for obtaining RGB (red, green, and blue) values for quantitative measurements. An open-source hardware electronic prototyping platform called Arduino, using an RGB color sensor TCS34725, was employed in the construction of the device, aiming at application in environmental samples. With the construction of this device, a portable and low-cost equipment was obtained. Tests were performed to verify the sensor's response to colored solutions, including tartrazine yellow, indigo, bromocresol green, ponceau red, and phenolphthalein, obtaining relative standard deviation (RSD) values less than 3 %, while the camera showed higher results when compared to the sensor. These studies indicate that the results obtained with the sensor have better precision compared to the use of smartphones. After this testing phase, the proposed device was applied to the determination of fluoride in water samples, based on the indirect spectrophotometric determination of fluoride, known as the SPADNS method.