Sulfate-S and other anions including Cl–, F– (with precautions), NO3-N and PO4-P, are included in the analytical suite described in more detail in Method 14E2a. Alternative IC technology, based on a single-column with electronic suppression of eluent conductivity, is provided as Method 14F5b.
Reagent Water
Deionised or distilled water, free of the anions of interest and containing no particles >0.20 μm.
Sulfate-S Primary Standard
1 L contains 1000 mg of SO4-S.
Prepare from a certified commercial standard solution or dissolve 5.4353 g potassium sulfate (K2SO4; previously dried at 105°C for 4 h) in Reagent Water and make to 1.0 L in a volumetric flask. This solution is stable for at least one month when stored at ≈4°C.
Mixed Working Standards
As for Method 14E2a.
Other Reagents
As for Method 5A3a/14E2a.
Ion Chromatograph, etc.
All details are similar to those provided in the corresponding section of Method 5A3a.
Analyse an aliquot of the SE (no particles >0.20 μm) by IC (chemical suppression of eluent conductivity) as outlined in Method 14E2a.
Report SO4-S/SE concentrations in cmolc/L, with relevant method codes, or multiply by 16.03 to convert to mg SO4-S/L.