A Sodium hydroxide - EDTA rinse is recommended for phosphorous and phosphate manifolds.
Prepare this solution with the instructions below:
Dissolve 65 g sodium hydroxide (NaOH) and 6 g tetrasodium ethylenediamine tetraacetic acid (Na4EDTA) in 1.0 L or 1.0 kg DI water.
The rinse helps remove coating from the combined color reagent and can be considered for blue staining or baseline noise and spikes. Dodecyl sulfate is added to the ascorbic acid in the reagent recipe to help address reagent coating during the run.
If necessary, at end of run place the color reagent and ascorbic acid transmission lines into the NaOH - EDTA solution. Pump this solution for approximately 5 minutes to remove any precipitated reaction products. Then place these lines in water and pump for an additional 5 minutes. Then air pump dry all lines.