The sensors have an electrode on either side. The electrodes are made from PVC end caps, sanded down flat at the tip. A hole is then drilled through the cap to accommodate a small machine screw.

The electrode detected PFOS at levels as low as 3.4 pM, well below the US Environmental Protection Agency’s health advisory level of 140 pM. “The next step is to optimize the selectivity of ...

This rests in a flat-bottomed chamber with a number of (12 in the demonstrator) regularly-spaced copper electrodes around the edge, with the rest of the floor covered in a water-repelling ...