Low-conductivity contacting-type conductivity measurement

摘要

A method of measuring low conductivity of a liquid sample using a contacting-type conductivity sensor is provided. The method includes applying a first excitation current to a contacting-type conductivity sensor at a first drive frequency. A first voltage response to the first excitation current is determined. A second excitation current is applied to the contacting-type conductivity sensor at a second drive frequency higher than the first drive frequency. A second voltage response to the second excitation current is determined. A conductivity output is provided based, at least in part, on the first and second voltage responses. A system for measuring conductivity of a liquid at or below 100 μS/cm is also provided.

主权项

1. A method of measuring conductivity at or below 100 μS/cm of a liquid sample using a contacting-type conductivity sensor, the method comprising:
applying a first excitation current using an analyzer, through a first pair of leads, to the contacting-type conductivity sensor at a first drive frequency, wherein the first pair of leads are placed in contact with the liquid sample having a source impedance that generates an error in conductivity measurement and wherein the excitation current at least partially extends through the liquid sample; determining a first voltage response through a second pair of leads of the contacting-type conductivity sensor to the first excitation current using the analyzer; applying a second excitation current using the analyzer, through the first pair of leads, to the contacting-type conductivity sensor at a second drive frequency different than the first drive frequency; determining a second voltage response through the second pair of leads of the contacting-type conductivity sensor to the second excitation current using the analyzer; providing a corrected conductivity output based, at least in part, on the first and second voltage responses wherein the corrected conductivity output is a function of the first and second voltage responses, and comprises a reduced error with respect to the source impedance; and wherein the second drive frequency is higher than the first drive frequency.