A dual intensity and lifetime based fluorescence sensor for perrhenate anion

Abstract

The development of fluorescence based sensor for perrhenate anion, which serves as a non-radioactive surrogate of hazardous pertechnetate anion, is an extremely rewarding task but nevertheless has remained rarely investigated in literature. Further, there are no reports in literature that propose a lifetime based sensing of perrhenate anion which provides significant advantage over pure intensity based sensor. Herein, we report an extremely simple fluorescence sensor for perrhenate anion in aqueous media, where we have used 1-pyrenemethylamine (PMA) as fluorescent probe. The fluorescence intensity of PMA is heavily quenched along with drastic reduction in the excited-state lifetime of PMA that provides an excellent opportunity for a very sensitive detection of perrhenate anion (LOD = 14 μM). Importantly, PMA also displays high selectivity towards perrhenate anion when compared with several other environmentally ubiquitous anions. The selective interaction between PMA and perrhenate has been attributed to the high basicity of ReO4− anion which facilitates a strong H-bonding interaction with amino group of the probe and the quenching interaction is attributed to the photoinduced electron transfer between excited PMA and ReO4−. Overall, an extremely simple, selective and sensitive fluorescence sensor for perrhenate anion is reported which also operates through lifetime measurement that is first of its kind.