Adsorption of Aqueous Copper Chlorophyllin Mixtures on Model Surfaces

Publication date: Available online 13 February 2020Source: Colloids and Surfaces A: Physicochemical and Engineering AspectsAuthor(s): Fengyan Wang, Yuichi Terazono, Jun Liu, Michael Fefer, Robert H. PeltonAbstractMeasured were the colloidal and adsorption properties of copper chlorophyllin (CuChl), a complex mixture derived from chlorophyll that is used as a food additive and in other applications. CuChl has an “apparent solubility” (it is a mixture) of 0.1 g/L in PBS buffer. Dynamic light scattering of dilute solutions showed the presence of particles with diameters in the range 10-200 nm. Nanoparticle tracking analysis (NanoSight LM10) showed the majority of nanoparticles had hydrodynamic diameters100-200 nm. Dialysis experiments revealed that 58% of a 0.1 g/L CuChl was present as dispersed particles. QCM-D measurements showed that aqueous CuChl adsorbs on surfaces giving a maximum adsorbed coverage, Γmax, that is sensitive to the type of surface; cellulose > polystyrene>> pullulan > silica = 0. No adsorption was observed on silica. Centrifuged CuCe6, a pure chlorin, showed essentially the same adsorption behaviors as centrifuged CuChl mixtures on polystyrene, suggesting that chlorins are the dominant adsorbed species from CuChl mixtures on hydrophobic surfaces. Centrifuged CuChl and CuCe6 usually gave lower Γmax values compared to non-centrifuged samples. In all cases, rinsing with buffer after CuChl or CuCe6 adsorption resulted in the immediate r...
Source: Colloids and Surfaces A: Physicochemical and Engineering Aspects - Category: Chemistry Source Type: research