A MATHEMATICAL-MODEL FOR THE VROMAN EFFECT

Adsorption and desorption at a surface are frequently the physical-che mical basis for boundary conditions used in analyzing bulk transport. The common Langmuir-like specifications of adsorption and desorption f ail to match observations if desorption does not occur, involves more than one adsorbed state for one or more molecular types, or depends st rongly upon the presence of particular dissolved species. In this pape r the Langmuirian formulation is generalized to account for such pheno mena. The result is fitted to data of Brash that quantify the Vroman e ffect, manifested as sequential adsorption of proteins from diluted bl ood plasma. The fitted parameters are then used to quantify ringlike p atterns of protein adsorption that have been observed when dilute plas ma is injected into the narrow space between a glass slide and a spher ical lens resting on it. Previous elaborations of the Langmuirian boun dary condition either fail to account for important qualitative featur es of complicated adsorption, or treat it with highly particular and n ot widely accepted parameters.