Highlights
•A microfluidic sensor for dissolved carbon dioxide determination in aqueous environments has been developed.
•The design of a microfluidic chip coupled with a white LED and a colour detector successfully formed the detection system.
•This is the first microfluidic device for the determination of dissolved CO2 that measures colour.
•The stability of the selected reagent has been studied for three months so far and is still stable.
•The result is a portable system for the determination of dissolved carbon dioxide from 7.2 ppm to 425.6 ppm.
In this work, we present a new system for the determination of dissolved carbon dioxide (from 7.2 ppm to 425.6 ppm) in aqueous environments. Microfluidic technology has been incorporated in sensor design to reduce the volume of samples and reagents. Moreover, a detection system has been integrated in the chip, consisting of a white light-emitting diode as a light source and a high-resolution digital colour sensor as the detector, which are able to detect changes in colour produced by the reaction of the sensing chemistry and carbon dioxide in water.
The optimised parameters found for the system are: flow rate 0.6 mL·min−1, integration time 30 s and the time for pumping of solutions was 3 min, obtaining a LOD of 7.2 ppm. The CO2 response, reproducibility, precision, and stability of the sensing chemistry have been studied and compared with those obtained using bench-top instrumentation (i.e. a spectrophotometer), obtaining good agreement.
Perez de Vargas Sansalvador I. M. , Lopez Ruiz N., Erenas M. M., Vallvey L. F. C., Coleman S., Diamond D., Fernandez Ramos M. D., in press. Towards an autonomous microfluidic sensor for dissolved carbon dioxide determination. Microchemical Journal. Article (subscription required).
