A colorimetric iron sensor based on the partition of phenanthroline complexes into polymeric hydrogels. Combinatorial synthesis and high throughput screening of the hydrogel matrix
A combinatorial library of 21 polymeric hydrogels is synthesized. A colorimetric high throughput screening allows to find out the materials which absorb the target complex: tris(phenanthroline)iron(II). A colorimetric sensor for iron(II) is built by loading bathophenathroline inside a poly(acrylamide-co-(-acrylamido-2-methylpropanesulfonic acid)) hydrogel. The sensor shows a detection limit of 0.1 ppm (colorimetric) and 0.01 ppm (spectrophotometric) for iron (II). The sensor is applied in the direct detection of iron content in milk, where direct colorimetric detection in solution is precluded due to the opacity of the sample.