Smoothly shifting fluorescent windows: a tunable "off-on-off" micellar sensor for pH.
The position of the window in an "off-on-off" fluorescent pH sensor may be shifted at will along a pH axis by changing the overall charge of the micellar container. This is obtained by using non-ionic Triton X-100 as the surfactant, and by increasing the molar fraction of the anionic sodium dodecyl sulfate (chi(SDS)) as co-surfactant, with pyrene as the fluorophore and a lipophilic tertiary amine and a lipophilic pyridine as pH-switchable quenchers. As the negative micellar charge increases by increasing chi(SDS), the observed pKa of the protonated bases move to higher pH values, followed by the dumb-bell shaped "off-on-off" fluorescence intensity vs. pH profile.
Pallavicini
Piersandro
P
Università di Pavia, Dipartimento di Chimica Generale, viale Taramelli, 12, 27100, Pavia, Italy. piersandro.pallavicini@unipv.it
Diaz-Fernandez
Yuri Antonio
YA
Pasotti
Luca
L
D000588:Amines / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D011199:Potentiometry; D011522:Protons; D011725:Pyridines / Q000737:chemistry; D013050:Spectrometry, Fluorescence
D000588:Amines; D008823:Micelles; D011522:Protons; D011725:Pyridines; C036252:N,N-dimethyl-1-dodecanamine; C023666:pyridine