An optical sensor for mercuric ion based on immobilization of Rhodamine B derivative in PVC membrane

A novel prepared mercuric ion PVC membrane sensor based on a Rhodamine B derivative (RND) as a selective sensing material was described. The sensor exhibited a specific fluorescent off-on response to Hg2+, and showed a linear response over the Hg2+ concentration range from 1.0 × 10−9 to 2.0 × 10−3 M with a very low detection limit of 8.1 × 10−10 M in bulk method. The sensor has also been incorporated into a flow-cell for determination of Hg2+ in flowing streams with improved sensitivity and detection limit. The sensor shows excellent selectivity toward Hg2+ with respect to common coexisting cations. The proposed fluorescence optode was successfully applied to detect Hg2+ in environmental water samples and fish.