Abstract: A technique for measuring concentration of ions in the parts per trillion range (10.sup.-5 to 10.sup.-6 milligram per liter) uses a new interconnection of ordinary components in a four step technique. In the first two steps, standard solutions of known, but widely different, concentrations are measured to determine a calibration factor (C) which is then applied in the second two steps to determine the very weak unknown concentration of the sample. The process can be automated and is useful in applications such as nuclear power plants where the presence of even very small concentrations of certain ions is undesirable because of the extreme conditions prevailing, and such as the semiconductor industry where extreme purity is required.

Abstract: A technique for measuring concentration of ions in the parts per trillion range (10.sup.-5 to 10.sup.-6 milligram per liter) uses a new interconnection of ordinary components in a four step technique. In the first two steps, standard solutions of known, but widely different, concentrations are measured to determine a calibration factor (C) which is then applied in the second two steps to determine the very weak unknown concentration of the sample. The process can be automated and is useful in applications such as nuclear power plants where the presence of even very small concentrations of certain ions is undesirable because of the extreme conditions prevailing.