engleski

Surface potential of beta-alanine at the electrolyte/air and artificial seawater/air interface

Surface potential and surface tension measurements in the concentration gradient from 10-7 to 10-1 mol dm-3 of beta-alaninein 10-4 mol dm-3 NaCl and in the artificial seawater of various salinities are done. Results show variations in the orientation of beta-alanine molecules on the air/solution interface, depending on beta-alanine concentration and salinity. For lower concentrations (below 2x10-3 mol dm-3)of beta-alanine in NaCl solution and for lower salinities (below 8%o) the carboxylic group (-COOH) is directed upward and the amino group (-NH2) downward (toward the liquid bulk), while the opposite is found at higher salinities and higher concentrations of beta-alanine. It is found from the dependence of the effective dipole moment, mi_ef, on the cencentration of beta-alanine, that, in the concentrati9on range brelow 10-3 mol dm-3, the dipole moment is simply related to 1/C. Above this concentration, the effective dipole moment is smammer and its value fluctuates.

beta-alanine; surface potential; dipolemoment; salinity gradient; seawater

nije evidentirano