Hydrogel coated fiber Bragg grating based chromium sensor

The present article reports a hydrogel coated Fiber Bragg Grating (FBG) based sensor for chromium metal ion detection. The presence of chromium metal ion in environmental water causes many toxic effects both on humans and animals. The inability of sensing traces of chromium ions is still remains a challenging problem for decades, as the Chromium exists in the environment in different oxidation states. This Paper discusses a chemo-mechanical-optical sensing approach for sensing harmful Chromium ions in environmental water. Fiber Bragg Grating is functionalized with a stimulus responsive hydrogel which swells or deswells depending on ambient chromium ion concentrations. This volume change of the hydrogels causes a bragg shift of the FBG peak. Different peak shifting’s, corresponding to different concentrations of the Cr ion concentrations, can be considered as a measure for quantifying traces of chromium ions. Hydrogel network cross-linked with (3-Acrylamidopropyl)-trimethylammonium chloride (ATAC) was synthesized and coated on FBG by dip coating method. Chromium ion concentrations up to ppm (parts per million) can be sensed by this technique.