Highly stable phospholipid/cholesterol electrode coatings for amperometric monitoring of hydrophobic substances in flowing streams.
Composite electrode coatings based on a mixture of phosphatidylcholine and cholesterol offer remarkable mechanical stability under vigorous hydrodynamic conditions. The greatly improved stability (over single-domain phospholipid layers) is attained without compromising the attractive permselective response of lipid electrodes. The enhanced stability is attributed to changes in the fluidity/packing associated with the presence of cholesterol. Due to its high stability, simplicity, and fast and permselective response, the coated electrode seems well-suited for flow measurements of hydrophobic compounds. Parameters affecting the film permeability and the amperometric response are explored in the presence of numerous solutes of biological and pharmaceutical significance. Prevention of surface fouling (in the presence of surfactants) and applicability to selective assays of urine samples are illustrated. Such controlled access to the surface, based on solute polarity, greatly enhances the power of electrochemical flow detectors.
Wang
J
J
Department of Chemistry, New Mexico State University, Las Cruces 88003.
Lu
Z L
ZL
D002627:Chemistry, Physical / Q000379:methods; D002784:Cholesterol; D004355:Drug Stability; D004563:Electrochemistry; D004566:Electrodes; D010743:Phospholipids
D010743:Phospholipids; D002784:Cholesterol