From home to road – from food to fuel, we knowingly or unknowingly come across adulteration in our daily lives. In India, it is known that various food products are adulterated. For example, more than 68% of milk is estimated to be adulterated, as per news reports. Automobile fuels, such as diesel and petrol, have also been found contaminated. Common adulterants in milk are wheat flour, urea, starch, detergent and hydrogen peroxide, while diesel and petrol are reported to have kerosene and naphtha.
Such adulterations have an adverse impact on the economy due to the significant variation in the prices of milk, fuel and adulterants. To understand the severity of the economic impact, it can be calculated that during the financial year 2015-16, milk and fuel adulteration had an economic burden of about Rs 4.1 lakh crore and Rs 1.40 lakh crore , respectively. Further, milk adulterants lead to health side effects , such as hormonal imbalance in children, sudden change in blood pressure leading to heart disease, kidney disease and diarrhoea. The fuel adulterants severely affect the engine life and the environment.
Historically, the purity and quality of milk could be checked through an organoleptic, clot on boiling or acidity test. For fuel adulteration, density, distillation, evaporation, gas chromatography and other tests have been used. All these tests are complex and time-consuming, requiring costly capital and experienced operators. Therefore, these tests may not be suitable for a common person to use, as well as for on-field and real-time monitoring.
Our work
Our research team has been engaged in developing an automated, inexpensive and fast-processing micro-device. Evidently, the milk-and-fuel adulteration with the aforementioned adulterants changes one of the unique properties of the liquid – viscosity, which measures resistance to fluid flow. The micro-device is amenable to monitoring the fluid viscosity within a desired window keeping accuracy and precision in mind.
One-time mathematical modelling and simulation was performed to understand the micro-device design parameters and the characteristics of the fluid’s flow. Subsequently, the micro-device (~3 cm x 2 cm x 0.2 cm) was fabricated using a 3D printer.
Overall, the 3D-printed device costs less than Re 1 and can be fabricated in 10 minutes. The capital cost of the 3D printer was about ₹ 80,000 , .
For milk adulteration, tests were performed when the pure milk was adulterated with water, wheat flour, urea and starch between 1-10%. Likewise, to monitor fuel adulteration, numerous samples of petrol adulterated with diesel and kerosene, and diesel adulterated with kerosene, were tested for their viscosities. The micro-device is amenable to measuring viscosity between 0.1 centipoise-30 cP with an accuracy of 98%. Hundreds of lab tests were extrapolated to correlate and optimise the viscosity of an unknown sample to the percentage of adulteration.
Platform tech
We’re now working to develop a fully automated, handheld device which can be integrated with a smartphone. With viscosity as the parameter, the device can potentially monitor any unknown fluid where viscosity remains the variable factor. We’re also trying to harness this device to analyse various blood constituents and properties, such as haemoglobin, triglycerides, haematocrit (refers to the volume of red blood cells in the blood) and coagulation. Clearly, such micro-devices can create a platform technology to monitor a physical parameter (viscosity in this case). These devices can be leveraged for multiple applications – from biochemical to biomedical — with the aim of realising fast and accurate products for mankind.
