Chelometric titrations with polyaminocarboxylic acids using barium and lead PVC-membrane ion-selective electrodes

Abstract EN

Barium and lead PVC-membrane i©n-selective electrodes have been tested as end-point detectors for the back titration of some metal ions with ethylenediaminetetraacetic acid (EDTA), ethyleneglycolbis tetraacetic acid (EGTA), and 1, 2-diaminocyclohexanetetraacetic acid (DCTA).

Metal ions studied were, Ca2+, Mg2+, Sr2+, Zn2+, Cu2+, Cd2+, Co2+, Ni2+, Mn2+, Al3+, and La3+.

Titrations have been carried out in the presence of either 10"3 M NaOH or acetate buffer of pH 5.5, when using the Ba-ISE or the Pb-ISE respectively as end-point detectors.

Ba2* or Pb2* standard solutions were used as the back titrants depending on the electrode used.

Concentrations of the tested metal ions in the final analyte solutions in all cases were in the range of 5xl0~5 to lxio-4 M.

The two electrodes worked successfully for most metal ions studied with relative standard deviations of about 1% and mean recoveries of about 100%.