| abstract |
First and second reactants that give a signal whennmixed in the presence of an analyte in a liquid sample, arenseparately contained in sol-gels that release the reactantsnin the presence of the liquid. For example, when the firstnand second reactants respectively comprise an oxidant andna reductant, and the reaction provides a detectable signal,nthe system can be used to detect the presence ofncontaminants in a water sample. The sol-gel may benobtained by reaction of water with, per part by volumenthereof, at least 2 parts of a metal alkoxide, and dryingnthe resultant gel. |