To provide a method and an apparatus for continuously measuring kind and concentration of a metal ion by a metal ion concentration-responsive hydrogel reversibly causing volume change in response to the change in metal ion concentration in control of water supply and drainage containing a metal ion.
A gel synthesized by using an N-alkyl(meth)acrylamide, (meth) acrylic acid or a (meth)acrylic acid salt as a main component causes reversibly remarkable swelling/shrinkage by the kind and amount of the metal ion as well as temperature and pH. The metal ion concentration can continuously be measured by observing the change in volume of the metal ion concentration- responsive hydrogel. A specific metal ion can selectively be detected by changing the kind and composition of the N-alkyl(meth)acrylamide, (meth)acrylic acid or (meth)acrylic acid salt and two or more kinds of metal ions can simultaneously and continuously be measured by using a plurality of gels.
FUJIOKA YUJI
SAITO KOUJI
IMAFUKU MUNEYUKI
