Study on various fluorescein derivatives as pH sensors

Abstract

Various fluorescein derivatives were examined as fluorescent pH sensors. Fluorescein derivatives bearing benzylic amine moieties displayed opposite fluorescent changes compared to those of simple fluorescein derivatives upon pH changes. Photo-induced electron transfer (PET) mechanism controls the fluorescent changes of these derivatives. In this Letter, modulations of pK a values were successfully demonstrated through variations of substituent groups. © 2011 Elsevier Ltd. All rights reserved.