226936-01-2Relevant articles and documents
Synthesis and characterisation of new fluorescent Na+ and K+ indicators
Ver Heyen, Katja,Cielen, Els,Tahri, Abdellah,Saleh, Ashty,Boens, Noel,Hoornaert, Georges J.
, p. 5207 - 5226 (2007/10/03)
The synthesis of new fluorescent indicators for Na+, Benz-15-5 or Diaz- 15-5, and for K+, Benz-18-6 or Diaz-18-6, respectively, is reported. They consist of a benzocrown or a diazacrown ether linked to a pyrazoline fluorophore substituted with carboxylate groups to ensure water solubility. They were obtained via reaction of an α,β-unsaturated ketone with an aryl hydrazine. The fluorescence intensity of Benz-15-5 is nearly insensitive to Na+. Benz- 18-6 displays a four-fold selectivity for K+ over Na+, with a dissociation constant of 3.6 mM for the K+: indicator complex. Diaz-15-5 and Diaz-18-6 have only a weak affinity for monovalent cations, so that they only can be used for the determination of high Na+ and K+ concentrations.