To measure DO in mg/L ,need to determine temperature ,salinity and pressure .I am using DO sensor which has temperature compensation also .Could you please help me to calculate DO by considering all this factors .
Any help or advice would be really appreciated.
Please see the below steps and let me know if any changes required to calculate DO and also suggest me the best way to calculate DO using galvanic probe.
Step one: Determine the % saturation, temperature, and salinity of the sample.
%Saturation = (mV in water/mV in air) * 100
--Sample is measured to have: 80% DO saturation 0 ppt salinity at 20º C(temp &salinity values are manually taken)
Upendra:How to measure salinity and temp using galvanic probe?
Step two: Multiply the % saturation reading by the value in appropriate column (depends on salinity) and row (depends on temperature) of the Oxygen Solubility Table.
Step two: Multiply .80 (which is the DO %) by 9.09 (value from oxygen solubility table at 0 salinity and 20º C) = 7.27 mg/L.
Result: 7.27 is the mg/L value that corresponds to an 80% DO Saturation reading of a sample with zero salinity at 20º C.
the mg/L concentration changes significantly with salinity and temp .
For example, oxygen saturated freshwater with 0 ppt salinity at 25ºC contains 8.26 mg/L of oxygen while oxygen saturated sea water (~36 ppt) at the same pressure and temperature contains only 6.72 mg/L of dissolved oxygen.
So what is the exact way to calculate DO using galvanic sensor probe by considering pressure ,salinity and temperature ?
Are there any formula to calculate accurate DO (mg/L) in relation with pressure ,temp and salinity without considering table manually ?
Kindly help me to solve this.
Thanks in advance .
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