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Capillary electrophoresis detection of a complex sensitive to electric field
Author(s) -
Messana Irene,
Andreasi Bassi Francesco,
Rossetti Diana V.,
Misiti Francesco,
Vincenzoni Federica,
Vitali Alberto,
Zuppi Cecilia,
Giardina Bruno,
Castagnola Massimo
Publication year - 2001
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/1615-9314(20010901)24:9<717::aid-jssc717>3.0.co;2-i
Subject(s) - chemistry , capillary electrophoresis , dissociation constant , dissociation (chemistry) , electrophoresis , analytical chemistry (journal) , electric field , hepes , acid dissociation constant , chromatography , biochemistry , physics , receptor , quantum mechanics , aqueous solution
This study describes the capillary electrophoresis detection of the weak interaction occurring between the negative form of 4‐(2‐hydroxyethyl)‐1‐piperazine‐ethanesulfonic acid (HEPES – ) and nicotinamide‐adenine dinucleotide (NAD + ). The ion‐paired complex is formed probably by 1 molecule of each reactant and it is sensitive to the applied electric field, since it was found that the value of the apparent association constant decreases as a function of the field applied. The association constant at zero field was obtained by extrapolation of the values determined at different applied field strengths and was found to be 2.0×10 3 M –1 . The peak convolution observed at the detection window was representative of a dissociation process that started at the beginning of the separation. The rate of the field‐induced dissociation corresponded to 6.4×10 –10 mol·cm·L –1 ·V –1 ·s –1 . Due to the complete absence of detectable signal shifts in 1 H‐NMR experiments, the interaction should be ascribed to the negative sulpho‐moiety of HEPES – and to the positive charge of the NAD + pyrimidine ring. To our knowledge, this is the first example of a “secondary Wien effect” observed at low field.