But test for what in those other instances? These sensor would have to be more complicated than most university labs to figure out poisons, toxins, quality, ppm, and more. In a lab, these tests are done using multiple pieces of equipment and following completely different means of testing.
I'm not knocking you, so please don't think I am. I just don't think the public at large has more than a rudimentary level of understanding when it comes to science.
Think of the basic process of having good ones blood taken at the doctors office. Behind the scenes, one little machine doesn't tell them all those nest numbers on liver function, kidney function, cholesterol, plasma and platelet levels, white blood cell count. Some of those are grouped together, but others are entirely different tests.