Rhodamine based NIR and ratiometric fluorescent sensor for selective identification of potassium ion: application in biological sample

Abstract

Fabrication of near infrared (NIR) and ratiometric chemosensors is very challenging task in supramolecular chemistry. For apprehension of such sensor, in the present manuscript, a thiourea derivative of rhodamine 1 is synthesized and characterized using 1 H, 13C NMR and mass spectrometry. Further organic nanoparticles (N1) are fabricated from receptor 1 by reprecipitation method. Upon interaction of N1 with K(I) ion, a new peak appeared at 678 nm with concomitant decrease of peak at 555 nm and thus it acted as ratiometric and NIR fluorescent probe; whereas with other metal ions there is no such appearance of peak. The binding of K(I) ion with N1 was confirmed with titrations with lowest detection limit of 36.86 nM. Further the applicability of N1 for K(I) ion was checked on real biological samples.