Helpful Hints on Colorimetric Fe Analysis

by Oliver Seely

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Your standard solution will develop a color like that shown in the image on the left. The blank solution is next to it for comparison.

The final procedure in the experiment involves determining the iron concentration in tap water contributed by students who have gathered samples from various locations. The absorbance of these samples generally is quite low, between 0.001 and 0.010. The color developed by a typical sample of tap water is shown in the image on the right.

One question at the end of the experiment refers to brown tea made alternatively using tap water and distilled water. Such preparations are shown in the image on the left. Thanks to student Hi- Jung Park for preparing this demonstration.

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