Determining ion concentration

A method for measuring the concentration of a desired ion in a solution comprising the steps of:

• (a) dividing the solution to be analyzed into a first and second portion,
• (b) treating the first portion with a first ion exchange resin which exchanges all of the ionic species in the solution with a charge opposite to that of the desired ion for a single ionic species,
• (c) passing the resultant solution from step (b) in contact with a first ion specific electrode which is specific to the single ionic species of step (b) or any ionic species for which the ions of said single ionic species have been exchanged,
• (d) treating the second portion of solution with a second ion exchange resin which exchanges all of the ionic species in the solution with a charge opposite to that of the desired ion for a single ionic species which then combine with the desired ions to form a substantially non-ionic product without substantial reaction with other ions in solution,
• (e) passing the resulting solution of step (d) in contact with a second ion specific electrode which is specific to the single ionic species of step (d) or any ionic species for which the ions of said single ionic species have been exchanged and said electrode is connected to the first ion specific electrode through a circuit which measures any imbalance in electrical potential between the electrodes, and
• (f) determining the concentration of the desired ion from the difference in electrical potential between said first and said second ion specific electrodes.

A method for measuring the concentration of a desired ion in a solution comprising the steps of:

• (a) dividing the solution to be analyzed into a first and second portion,
• (b) treating the first portion with a first ion exchange resin which exchanges all of the ionic species in the solution with a charge opposite to that of the desired ion for a single ionic species,
• (c) passing the resultant solution from step (b) in contact with a first ion specific electrode which is specific to the single ionic species of step (b) or any ionic species for which the ions of said single ionic species have been exchanged,
• (d) treating the second portion of solution with a second ion exchange resin which exchanges the ionic species in the solution with a charge opposite to that of the desired ion for a single ionic species which then combines with the desired ionic species to form a substantially non-ionic product without substantial reaction with other ions in solution wherein said ion exchange resin exchanges a sufficient amount of the ionic species to result in the combination of all of said desired ionic species to form a substantially non-ionic product,
• (e) treating the resultant solution of step (d) with a third ion exchange resin which exchanges all of the ionic species in said resultant solution with a charge opposite to that of the desired ion for a single ionic species,
• (f) passing the resulting solution of step (e) in contact with a second ion specific electrode which is specific to the single ionic species of step (e) or any ionic species for which the ions of said single ionic species have been exchanged and said electrode is connected to the first ion specific electrode through a bridge circuit which measures any imbalance in electrical potential between the electrodes, and
• (g) determining the concentration of the desired ion from the difference in electrical potential between said first and said second ion specific electrodes.

An apparatus useful in measuring the ion concentration of a desired ion in a solution comprising,

• means for splitting said solution into a first and second portion,
• means defining a precipitation zone having means for receiving one of the portions of said solution and means for removing the desired ion from solution,
• means defining at least a first and second ion exchange zone comprising an ion exchange resin which is capable of exchanging the ionic species in the solution contacted therewith which have a charge opposite to that of the desired ion for a single ionic species,
• a detection means comprising a first and second ion specific electrode connected to a bridge circuit for detecting the difference in electrical potential between the two ion specific electrodes,
• conduit means for passing the first portion of said solution to the first ion exchange zone and the second portion of said solution to the precipitation zone,
• conduit means connecting said first ion exchange zone to the detection means with access to the first ion specific electrode which is specific to the single ionic species in that portion of the solution, and
• conduit means for passing the solution from the precipitation zone to the second ion exchange zone and then connecting said second ion exchange zone to the detection means with access to the second ion specific electrode which is ion specific to the single ionic species in that portion of the solution.

Method for measuring the concentration of desired ions in a solution, said solution containing first feed ions of a first charge in an initial concentration, second feed ions of a second charge opposite to the first charge in an equivalent concentration and containing among the first feed ions the desired ions to be measured, said method comprising,

• (a) generating a reference stream from said solution containing only such ions in one charge to which a reference electrode is sensitive, and containing these ions in a concentration equivalent to said initial concentration,
• (b) passing this reference stream into contact with said reference electrode,
• (c) generating a measurement stream from said solution,
• (d) converting the desired ions of said measurement stream to a non-ionic product and leaving an intermediate measurement stream having an ion concentration equivalent to the difference of the initial ion concentration minus the concentration of said desired ions and deriving a final measurement stream from the intermediate measurement stream such that the final measurement stream contains only such ions of one charge to which a measurement electrode is sensitive,
• (e) passing the final measurement stream derived from the intermediate measurement stream of step (d) and containing only such ions of one charge to which a measurement electrode is sensitive and containing these ions in a concentration equivalent to the initial ion concentration minus the concentration of said desired ions, into contact with said measurement electrode, and
• (f) determining the relative electrical potential between the measurement electrode and the reference electrode.

Apparatus for measuring the ion concentration of a desired ion in a solution comprising

• (a) means defining a source of said solution,
• (b) first means to convert at least a first portion of said solution into a reference stream containing only such ions of one charge in a concentration equivalent to the initial concentration of said solution, to which ions a reference electrode is sensitive,
• (c) second means for converting a second portion of said solution into a final measurement stream containing only such ions of the same charge as the charge mentioned in (b) to which ions a measurement electrode is sensitive, in a concentration equivalent to said initial concentration minus the concentration of said desired ions, said second means comprising non-ionic product generating means for converting said desired ions into a non-ionic product,
• (d) conduit means connecting said source of said solution to said first and said second means,
• (e) a measurement electrode sensitive to the specific ions of (c)
• (f) a reference electrode sensitive to the specific ions of (b)
• (g) measurement conduit means connecting said first means with said reference electrode,
• (h) reference conduit means connecting said second means with said measurement electrode,
• (i) potential detector means attached to said electrodes capable of detecting the electric potential between said electrodes and of generating an information signal representative of said electric potential.