Abhishesh Pal, Sohan Dudala, Satish Kumar Dubey and Sanket Goel are a team at MEMS, Microfluidics & Nanoelectronics (MMNE) lab who are is working towards realizing futuristic smart sensors and intelligent energy harvesters encompassing various multidisciplinary domains. While MMNE Lab strives to develop state-of-the-art technologies in sensing, the focus is to keep societal applications, user-frindly and affordable at the centre of the entire process value chain. An array of pollutants are responsible for water quality deterioration; nitrayes and nitrites being the highest pollutants. Being highly soluble in water, they have the amenability to reach potable water sources. These constituents, beyond prescribed limits, have adverse effects on human health, including ailments such as methemoglobinemia (blue-baby syndrome) which might be fatal to infants. Chronic exposure to these nitrites and nitrates has also been linked to certain cancers.

The effective management of the excesses starts with proper, rapid and affordable identification, i.e. sensing. To facilitate the same, MMNE lab has developed a standalone, point-of-source, portable, low-cost, automated, and integrated system for rapid detection and quantification of nitrites (Figure 1). The system was developed based on the application of Beer–Lambert law where a microfluidic device was fabricated to carry out a colourimetric reaction to quantify nitrites in the water. An android smartphone application was developed to control the complete system and store the data. The sensing platform relied on cost-effective fabrication techniques such as 3D printing and clean room-free device development. The platform offered a detection limit 10 times lower than that specified by World Health Organization, making it effective in sensitive quantification in portable settings. The component cost of the developed system stood at ₹2,200 (US$ 33).