Abstract
A multi-purpose concentration sensor (MPCS) for organic compounds/gases or other compounds/gases tests the concentration of target content of the compound/gas such as methanol dissolved in certain solvents like water, where the exemplary methanol solution is called target solution, where the sensor can optionally or alternatively test the concentration of gas state target content like methanol vapor in a gas mixture and where the gas mixture to be tested is called target gas. The MPCS comprises two chambers or flow passages, a 'separate' structure, one or more diffusion or transport structures, one or more transfer structures, optionally includes one or more temperature control structures, one or more aim sensors, and optionally, one or more thermal management structures.