S.No
Foreign ions
Tolerance [interference/vanadium(V)]
1
Cl−, F−
15
2
, 
10
3
Na+, Ca2+, Zn2+, Fe3+, Fe2+, Cu2+
8
4
Cr3+, EDTA
5
5
Mn2+, Co2+, Ni2+
4
| S.No | Foreign ions | Tolerance [interference/vanadium(V)] |
| 1 | Cl−, F− | 15 |
| 2 |
| 10 |
| 3 | Na+, Ca2+, Zn2+, Fe3+, Fe2+, Cu2+ | 8 |
| 4 | Cr3+, EDTA | 5 |
| 5 | Mn2+, Co2+, Ni2+ | 4 |