As the fossil fuels are depleting with time, the concerns and research work in the area of renewable energy is growing; thereby providing ample scope for the production of biofuels. Due to different fuel-combustion properties, the blends of biofuel with conventional fuels can be used as an automobile fuel. The existing methods to detect this blending ratio have heavy one-time test cost, need of a controlled environment, requirement of a dedicated or experienced operator, and expensive testing-and-measurement equipment. Today a device is required, to monitor the composition of the fuel in automobiles which is easily deployable, robust, user-and-equipment friendly, in-situ, and inexpensive. It is well observed that the fuel mixture directly affects the lubricating properties of the fuel and therefore directly affecting the engine performance. As the lubricating properties are simply related to the different physical properties, developing a sensor, based on such physical properties, can provide a reliable and effective solution to detect and monitor the fuel blending. This work describes the development of a micro-device able to perform various fluidic operations by observing and analyzing different physical properties and their variation. These devices are fabricated using well-established micro-fabrication techniques which are inexpensive on mass-production, and can potentially be integrated with the existing microcontrollers in the automobiles. The test results of various samples with different blending ratios clearly distinguish the diesel blending with different quantities of bio-diesel. The detection and measurements of different physical properties of such blended-fuels, along with their comparison to conventional techniques, will be presented. Such microfluidic devices have prospects for various investigations, to understand different physical properties in a wide range of hydrocarbons or hydrocarbon compositions.