Not just a background: pH buffers do interact with lanthanide ions-a Europium(III) case study

The interaction between Eu(III) ion and different pH buffers, popular in biology and biochemistry, viz. HEPES, PIPES, MES, MOPS, and TRIS, has been studied by solution nuclear magnetic resonance spectroscopy (NMR) and time-resolved laser-induced fluorescence spectroscopy (TRLFS) techniques. The Good's buffers reveal non-negligible interaction with Eu(III) as determined from their complex stability constants, where the sites of interaction are the morpholine and piperazine nitrogen atoms, respectively. In contrast, TRIS buffer shows practically no affinity towards Eu(III). Therefore, when investigating lanthanides, TRIS buffer should be preferred over Good's buffers. [GRAPHICS] .

Automated summary

The interaction between Eu(III) ion and different pH buffers was studied using NMR and TRLFS techniques. The results showed that Good's buffers have significant interaction with Eu(III), while TRIS buffer has practically no affinity towards Eu(III). Therefore, TRIS buffer should be preferred when investigating lanthanides.