Paper-based microfluidic sensor devices for inorganic pollutants monitoring in water

The ideal environmental sensing devices should include following features: autonomous operation; robustness to sustain the extreme environmental stresses, features to undertake quantitative and qualitative measurements with desired sensitivity and reproducibility. The requirement for portable and self-operated devices is crucial in gaining insights to understand potential environmental hazards in all core environments, namely, water, air, land, and biological matrices. There are a variety of environmental contaminants, which require regular monitoring to assess the impacts and to arrive at remedial measures. Several standard analytical techniques are available for monitoring of these contaminants, including laboratory-based spectroscopic and chromatographic techniques. These techniques are highly sensitive and selective; however, they are exorbitantly costly, lack portability as they are bulky, and require highly skilled professional operators and laborious operations. Therefore big challenge remains in developing low-cost, portable, and highly efficient field testing devices. Recently microfluidics has evolved as a reliable technology for affordable and portable detection platforms. Recent efforts to develop microfluidic devices mainly focused on the development of integrated microfluidic devices by incorporating fluidic components and analytical and detection techniques into single platform. Tailored microfluidic devices are being developed to address a variety of applications, including determination of air, water, and food quality and detection of pathogens, biofilms, and environmental contaminants. Paper-based microfluidic devices have been developed recently to reduce the cost and due to other advantageous features such as disposability, portability, and requirements of low volume of samples. The chapter offers a comprehensive insight into recent developments pertaining to materials and techniques for detection and fabrication of paper-based microfluidic devices.