ESTIMATION OF EFFECTIVE FIXED CHARGE-DENSITY OF A BLACK LIPID-MEMBRANE OF DIDODECYL PHOSPHITE FROM MEMBRANE-POTENTIAL AND ITS APPLICATION TO STATIC MAGNETIC-FIELD EFFECT ON ION-TRANSPORT

The membrane potential of black lipid membranes (BLM), formed from 20 ppm didodecyl phosphite in (3 + 2) octanedodecane containing 1% choles terol, has been measured across a BLM separating solutions of 1:1 salt s (NaCl and KCl) at 25 degrees C in the absence and presence of a 1.5- kG static magnetic field, The membrane potential decreased when the ma gnetic field was applied perpendicular to the BLM, These data have bee n used to evaluate the effective fixed charge density and the permsele ctivity for ions of the BLM. The magnetic effects on the membrane pote ntial of the BLM are quantitatively interpreted by the estimated param eters from the preliminary results measured under the magnetic field: the 20-30% increase in the effective charge density of the BLM and the associated promotion of the permselectivity of the BLM. (C) 1996 Acad emic Press, Inc.