System and method to measure dissolved gases in liquid

A method for continuously measuring the concentration of at least one pre-selected dissolved gas in a sample water obtained from a quantity of water during a selected time period, comprising:

• selecting a sample processing cell having at least a first conduit defining a first passage with at least one wall for passing at least the pre-selected dissolved gas from the sample water into an indicator liquid, the at least one gas-permeable wall resisting flow of the sample water therethrough, the at least one gas-permeable wall extending along a second conduit through which the sample water is conducted, and the at least one gas-permeable wall being in contact with the sample water in the second conduit;
• continuously directing indicator liquid through the first conduit while continuously moving the sample water and the indicator liquid relative to each other in a countercurrent flow relationship while being separated from one another via the at least one gas-permeable wall to generate at least partially equilibrated indicator liquid;
• optically measuring the concentration of the dissolved gas in the at least partially equilibrated indicator liquid obtained from the first conduit utilizing a device that is separate from the sample processing cell and which enables measurement after the at least partially equilibrated indicator liquid exits from the sample processing cell;
• and
• wherein the indicator liquid is moved continuously through the sample processing cell and through the separate device during measuring while the sample water is moved continuously through the sample processing cell.