Methods for analyzing solder plating solutions

A method for determining tin concentration in a sample solder plating solution comprising tin and lead ions, by titrating said sample solder plating solution with a titration solution that comprises a material selected from the group consisting of iodine and iodide, and by measuring reduction-oxidation potential responses of said sample solder plating solution, during the titration, said method comprising the steps of:

• (a) adding a stabilizing solution into the sample solder plating solution, for stabilizing the lead ions therein to prevent precipitation of said lead ions during subsequent titration;
• (b) titrating the sample solder plating solution with the titration solution comprising iodine;
• (c) monitoring oxidation-reduction potential of the sample solder plating solution during the iodine titration by using an oxidation-reduction potential electrode, for determining an end point of said titration;
• and
• (d) calculating the tin concentration in the sample solder plating solution, based on the titration end point determined in step (c),
• wherein the oxidation-reduction potential electrode comprises dual polarized platinum electrodes.