Fluorescent molecular probes III. 2′,7′-Bis-(3-carboxypropyl)-5-(and-6)-carboxyfluorescein (BCPCF): a new polar dual-excitation and dual-emission pH indicator with a pKa of 7.0

2′,7′-Bis-(3-carboxypropyl)-5-(and-6)-carboxyfluorescein (BCPCF) was prepared and characterized as a new polar dual-excitation and dual-emission pH indicator with a pKa of 7.0.