A Pyrazolo Imine‐based Colorimetric and Turn‐on Fluorescent Sensor Probe for Determination of Hg<sup>2+</sup> Ion and its Application in Test Paper Strips
Uma Maheswari Krishnan, Sathiyanarayanan Kulathu Iyer
Abstract
Abstract In this work, we synthesized diethylamino substituted pyrazolo imine ( 3 ) fluorescent probe for recognition of Hg 2+ ion.The sensor probe 3 can detect Hg 2+ by colorimetric method, and there is a 10‐fold enhancement in fluorescence response. When the fluorescent probe bound with Hg 2+ ion, turn‐on fluorescence was observed via the coordination. Probe 3 has an excellent selectivity toward Hg 2+ in the CH 3 CN/H 2 O (8:2, v/v) solution with low limit of detection and high binding association constant of 551 parts per billion (ppb) and 6.6067 × 10 6 m −1 for 3+Hg 2+ , respectively. Furthermore, the formation of 3+Hg 2+ complex with 1:1 binding mode was evidenced by Job's plot, 1 H NMR spectroscopy and Mass analysis. In addition, probe 3 is a feasible option to detect Hg 2+ in various sources of water samples. Bio‐imaging experiments have demonstrated that probe 3 can be used to monitor Hg 2+ in Escherichia coli bacterial cell. The sensor 3 was also used for paper strip application to detect Hg 2+ ion.