Ajcharapan TantipanjapornSamran PrabpaiKanoknetr SuksenPalangpon KongsaereeMahidol University2019-08-232019-08-232018-03-05Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy. Vol.192, (2018), 101-107138614252-s2.0-85032922452https://repository.li.mahidol.ac.th/handle/20.500.14594/45502© 2017 Elsevier B.V. A rhodamine-thiourea conjugate RTP with an o-phenylenediamine linker was developed as a fluorogenic chemodosimeter for Hg2+ detection. In the presence of Hg2+, a colorless solution of RTP turned pink with a maximum absorption band at 555 nm and with a 62-fold fluorescence enhancement at 578 nm (Φ = 0.34). RTP is highly selective to Hg2+ among other metal ions with a detection limit of 1.6 nM (0.3 ppb). A similar rhodamine analog with a flexible ethylenediamine spacer was less selective and less sensitive than RTP. Hg2+ induced cyclic guanylation to yield a benzimidazole moiety and a subsequent ring-opening of the spirolactam unit resulted in chromogenic and fluorogenic changes. The membrane-permeable RTP probe was successfully demonstrated in monitoring of Hg2+ in cultured HeLa cells.Mahidol UniversityChemistryPhysics and AstronomyArticleSCOPUS10.1016/j.saa.2017.10.057