Page 15: Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Ammonia
| Methodology | Method ID | Range of application (mg/L as N) |
Detection level (mg/L as N) |
Interferences / recommended action |
Comments |
|---|---|---|---|---|---|
| Colorimetry | U.S. EPA 350.1 | 0.02-2.0 | 0.01 | Ca2+, Mn2+ / use EDTA Residual Cl2 / use dechlorinating agent Elevated turbidity and colour / filter sample High Ca2+, Mn2+ / complex with citrate Turbidity / distil or filter water |
Linear up to 0.6 mg/L as N |
| SM 4500-NH3 F (phenate method) |
< 0.6 | ||||
| SM 4500-NH3 G (automated phenate method) |
0.02-2.0 | High turbidity or colour / filter sample High Ca2+, Mn2+ / add EDTA and sodium tartrate |
Avoid high variability in pH of samples: intensity of colour measured is pH dependent | ||
| SM 4500-NH3 H (automated flow injection) |
0.002 | Large and fibrous particles / filter sample | Some interferences may be removed by distillation | ||
| U.S. EPA 350.2 (nesslerization) |
0.05-1.0 | 0.05 | Aromatics, amines / distil water Volatile alkaline compounds / boil off at low pH Residual Cl2 / use dechlorinating agent |
Dropped from the Standard Methods to avoid use of mercury | |
| Titrimetry | U.S. EPA 350.2 | 1.0-25 | 1.0 | Residual Cl2 / use dechlorinating agent | Sample distillation is required |
| SM 4500-NH3 C | 5.0-100 | Residual Cl2 / use dechlorinating agent | Sample distillation is required | ||
| Potentiometry: ammonia ion-selective electrode | U.S. EPA 350.3 SM 4500-NH3 D |
0.03-1400 | 0.03 | Elevated concentration of dissolved ions, Hg / do not preserve sample with HgCl2 | Turbidity and colour do not interfere; distillation not required; slow response below 1 mg/L as N |
| SM 4500-NH3 E (using known addition) |
> 0.8 | Elevated concentration of dissolved ions, Hg / do not preserve sample with HgCl2 | Can be applied in the presence of high complexing agents |