Table 1. Uncertainty Budget for the Measurements of Iron(III).
| uncertainty source | relative
standard uncertainty, % |
||
|---|---|---|---|
| path A (thiosulfate) | path B (EDTA) | path C (Ti) | |
| standard (potassium iodate, iron, and potassium dichromate) | 0.011 | 0.050 | 0.008 |
| repeatability against the standard | 0.0023 | 0.0041 | 0.168 |
| repeatability against the sample | 0.038 | 0.0034 | 0.114 |
| weighing of the standard | 0.0013 | 0.0003 | 0.0009 |
| weighing of titrants | 0.0005 | 0.0010 | 0.0005 |
| weighing of the sample | 0.0011 | 0.0003 | 0.0008 |
| combined standard uncertainty | 0.040 | 0.050 | 0.20 |
| expanded uncertainty (k = 2) | 0.080 | 0.10 | 0.40 |