Measuring nitric oxide in fluid

A method for measuring a dissolved gas in a fluid comprising:

• adding the fluid into a sample chamber of a disposable cartridge configured to be coupled to a reusable instrument component having an electrochemical sensor;
• transferring the fluid from the sample chamber to a sample degassing chamber;
• liberating the dissolved gas from the fluid within the sample degassing chamber, wherein liquid and solid residue is retained within the sample degassing chamber following liberating of the dissolved gas;
• capturing the liberated gas in a carrier gas contained within the sample degassing chamber;
• providing the liberated gas in the carrier gas to the reusable instrument component;
• and
• measuring the dissolved gas concentration using the electrochemical sensor.