Determination of the Copper (II) Ions with complexometric titration using a Cu-ion selective electrode. Other metalls (II) can be determine also with a addition of Cu-EDTA. The samples are normally buffered in a acetate- or ammonia buffer (pH 10). All metalls who form a lower stable metall EDTA complex than Cu-ETDA can be analysed with this method. That are e.g. Mg, Ca, Zn, Pb, Cd, Mn und Co2+.