a disposable sensor card includes a polymeric substrate , such as polyester , printed with a plurality of electrodes , and a reuse - prevention system which includes a fuse link and a cut link . a controller tests the fuse link and cut link to see if they have been destroyed . if the controller determines that the two links are good , a sensor card support system , which includes a ram , clamps the sensor card over an opening in a manifold so that the electrodes are in contact with a decontaminant solution , such as peracetic acid solution , passing through the manifold . the controller detects an electrical property of the electrodes and determines a concentration of the decontaminant therefrom . during the clamping process , a cutter severs the cut link . a memory of the cut link is retained by the controller . if power to the controller is interrupted , the memory is lost and the controller detects that the cut link is broken when power is regained . at the end of a decontamination process , the controller switches to a “ power off ” mode and detects that the cut link is severed . when the controller detects that the cut link is severed , the controller blows the fuse link and the sensor card support system unclamps the sensor card . the severed cut link provides a visual indication that the card is spent .