Table 1

The relative standard deviation in the determination of ferric ions (%)
Ferric ions (mg/L) Within the day RSD (%) Between days RSD (%)
A480 A480
Mean SD Mean SD
0 0.0458 0.0027 5.93 0.0462 0.0025 5.32
0.31 0.0540 0.0008 1.48 0.0554 1.90 × 10−3 3.43
0.62 0.0665 0.0031 4.68 0.0682 0.0038 5.58
1.25 0.0878 0.0013 1.47 0.0894 2.00 × 10−3 2.25
2.5 0.1301 0.0029 2.23 0.1329 0.004 2.97
5 0.2187 0.0049 2.25 0.2253 0.0093 4.13
10 0.4111 0.0084 2.03 0.4219 0.0127 3.02
20 0.8206 0.0297 3.61 0.846 0.0343 4.05
40 1.6834 0.027 1.60 1.6896 0.0202 1.20
80 3.442 0.0633 1.84 3.4985 0.0851 2.43
100 4.2956 0.0671 1.56 4.3911 0.1499 3.41
200 5.9739 0.036 0.60 5.9739 0.036 0.60

The RSD at different concentrations of ferric ions was the relative percentage of the standard deviation with mean value calculated from three determinations of ferric ions in 1 day or 3 days, respectively.

Wu et al.

Wu et al. Nanoscale Research Letters 2012 7:665   doi:10.1186/1556-276X-7-665

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