Table 3 Comparison of actual Fe(II) concentrations to those predicted by the pilot ion method
K = 2.43 | |||
|---|---|---|---|
i(Fe), nA | predicted cFeμM | actualcFe | Difference |
August 19, 2010 | |||
Electrode 1 | |||
c pilot | 110 | ||
i pilot | 6.02 | ||
0.0976 | 4.342 | 6.042 | −28% |
0.2265 | 10.076 | 12.08 | −17% |
0.5873 | 26.13 | 24.16 | 8.1% |
1.182 | 52.58 | 48.31 | 8.8% |
2.347 | 104.41 | 96.5 | 8.2% |
4.541 | 202.0 | 168.7 | 20% |
6.734 | 299.6 | 252.7 | 19% |
Electrode 2 | |||
c pilot | 110 | ||
i pilot | 7.441 | ||
0.3043 | 10.95 | see above | 81% |
0.4153 | 14.95 | 24% | |
0.6217 | 22.38 | −7.4% | |
1.062 | 38.22 | −21% | |
2.142 | 77.09 | −20% | |
3.559 | 128.1 | −24% | |
5.488 | 197.5 | −22% | |
Electrode 3 | |||
c pilot | 110 | ||
i pilot | 13.41 | ||
0.2902 | 5.796 | see above | −4.1% |
0.5201 | 10.387 | −14% | |
1.26 | 25.16 | 4.2% | |
2.322 | 46.37 | −4.0% | |
4.896 | 97.78 | 1.3% | |
9.168 | 183.1 | 8.5% | |
13.39 | 267.4 | 5.8% | |
August 20, 2010 | |||
Electrode 1 | |||
c pilot | 110.03 | ||
i pilot | 8.441 | ||
0.3771 | 11.97 | 6.01 | 99% |
0.4613 | 14.64 | 12.02 | 22% |
0.8352 | 26.51 | 24.03 | 10% |
1.711 | 54.30 | 48.03 | 13% |
3.212 | 101.94 | 95.99 | 6.2% |
5.402 | 171.4 | 167.8 | 2.2% |
8.383 | 266.0 | 251.3 | 5.9% |
Electrode 2 | |||
c pilot | 110.03 | ||
i pilot | 7.059 | ||
0.3043 | 11.55 | see above | 92% |
0.4153 | 15.76 | 31% | |
0.6217 | 23.59 | −1.8% | |
1.062 | 40.30 | −16% | |
2.142 | 81.29 | −15% | |
3.559 | 135.1 | −20% | |
5.488 | 208.3 | −17% | |
Electrode 3 | |||
c pilot | 110.03 | ||
i pilot | 7.685 | ||
0.3106 | 10.83 | see above | 80% |
0.4024 | 14.03 | 17% | |
1.247 | 43.47 | −9.5% | |
2.665 | 92.90 | −3.2% | |
4.477 | 156.1 | −7.0% | |
6.795 | 236.9 | −5.7% | |
Average differences | |||
<15 microM | 46% | ||
>25 microM | 13% | ||
Overall | 20% | ||