New fluorescent pH sensors based on covalently linkable PET rhodamines

作者：Aigner Daniel; Borisov Sergey M^*; Orriach Fernandez Francisco J; Fernandez Sanchez Jorge F; Saf Robert; Klimant Ingo

来源：Talanta, 2012, 99: 194-201.

DOI：10.1016/j.talanta.2012.05.039

• pH sensor
• Fluorescence
• Rhodamine
• Photoinduced electron transfer
• Covalent dye coupling
• %26quot
• Click%26quot
• chemistry

A new class of rhodamines for the application as indicator dyes in fluorescent pH sensors is presented. Their pH-sensitivity derives from photoinduced electron transfer between non-protonated amino groups and the excited chromophore which results in effective fluorescence quenching at increasing pH. The new indicator class carries a pentafluorophenyl group at the 9-position of the xanthene core where other rhodamines bear 2-carboxyphenyl substituents instead. The pentafluorophenyl group is used for covalent coupling to sensor matrices by %26quot;click%26quot; reaction with mercapto groups. Photophysical properties are similar to %26quot;classical%26quot; rhodamines carrying 2%26apos;-carboxy groups. pH sensors have been prepared with two different matrix materials, silica gel and poly(2-hydroxyethylmethacrylate). Both sensors show high luminescence brightness (absolute fluorescence quantum yield Phi(F) approximate to 0.6) and high pH-sensitivity at pH 5-7 which makes them suitable for monitoring biotechnological samples. To underline practical applicability, a dually lifetime referenced sensor containing Cr(III)-doped Al2O3 as reference material is presented.

• 出版日期2012-9-15