Detection of chromium using polymer coated etched FBG

Abstract

A chemo-mechanical-optical sensing technique is presented in this paper to detect carcinogenic Chromium Cr(VI) metal ion utilizing etched FBG (Fiber Bragg Grating) coated with stimulus responsive hydrogel. The Hydrogel is formed with blends of p(AMPSNa-co-APTMACl) which are greatly responsive to Cr (chromium) ions and exhibit a volume variation whenever dipped in the Cr solution. When the sensor head is exposed to different hexavalent Chromium (VI) ion concentration solutions, it exhibits a peak shifts because of the induced mechanical strain through the gel swelling. Chromium (VI) ion concentration is correlated with the peak shift. The sensor’s sensitivity is observed to be 15.1 pm/ppb which is 10 times the sensitivity of an unetched gel coated FBG sensor. The Cr (VI) ions trace amount is as low as 10 ppb will be sensed through technique. The proposed sensor has exhibited better repeatability, selectivity and sensitivity and the significant features of the proposed sensor are less weight, adoptability and compact size to monitor remotely.