Interaction of ortho- and para-nitrophenol with lipid monolayers studied by monolayer techniques and reflection spectroscopy

Abstract

Abstract The differences in interactions of ortho - and para -nitrophenol (ONP and PNP) with lipid monolayers have been studied by monolayer techniques and reflection spectroscopy. Two different systems have been compared: (1) monolayers of dipalmitoylphosphatidylcholine (DPPC) on a subphase containing nitrophenols and trimethyloctadecylammonium bromide (TOMA) and (2) monolayers of docosylpyridinium bromide (DPyBr) on a subphase containing nitrophenols. The average orientation of nitrophenolate ions bound to neutral and positively charged monolayers was estimated by measuring the reflection of polarized light under oblique incidence.