ATR-FTIR study of lipopolysaccharides at mineral surfaces

Nano-scale investigation of the association of microbial nitrogen residues with iron (hydr)oxides in a forest soil O-horizon

“…Various studies show that microbial lipids tend to be enriched in clay-sized soil mineral fractions (Baldock et al, 1992;Guggenberger et al, 1995;Clemente et al, 2011). One possible explanation is the large sorptive affinity of phospholipids to the surfaces of clay-sized Fe (hydr)oxide minerals (Omoike et al, 2004;Parikh and Chorover, 2008;Cagnasso et al, 2010). For instance, Cagnasso et al (2010) demonstrated the rapid formation of inner-sphere complexes between phosphate groups of bacterial cell membrane phospholipids and hydroxylated Fe oxide surfaces.…”

In-situ monitoring of Cryptosporidium parvum oocyst surface adhesion using ATR-FTIR spectroscopy

“…The intensity increase of the band at 1023 cm −1 corresponding to sugar ring vibrations may be caused by the ring structure change due to the treatment. In addition, while viable oocysts generally exhibit hydrophilic properties and the ZnSe surface is relatively hydrophobic [35], formalin treatment was reported to substantially increase the hydrophobicity of oocysts [18]. This enhancement of hydrophobicity may partially explain the increase in oocyst adhesion at the ZnSe surface.…”

“…Spectra were obtained using a trough-style sample holder with a zinc selenide (ZnSe) internal reflection element (Spectra-Tech ARK ATR cell) (70 mm × 10 mm × 3 mm) subjected to a nominal incident angle of 45 • , yielding 12 internal reflections at the sample surface [34]. The surface of the ZnSe IRE exhibits an isoelectric point <4 and relatively hydrophobic properties [28,35]. To examine the time dependence of surface interactions, spectra were collected as a function of time (mean times of 4, 19, 34, 64, and 124 min after sample introduction) at 25 • C. A volatile liquid cover was used to prevent solution evaporation.…”

Adsorption of sodium dodecyl sulfate (SDS) at ZnSe and α-Fe2O3 surfaces: Combining infrared spectroscopy and batch uptake studies

“…At the ZnSe IRE surface, in addition to electrostatic interactions, hydrophobic interactions between the hydrocarbon tail of the surfactant and the surface are expected to play a role in adsorption. Given the negative surface charge of the ZnSe surface (pzc $ pH 4) at the experimental pH and the greater hydrophobicity of ZnSe relative to a-Fe 2 O 3 [29], it is plausible that SDS ions interact with the ZnSe surface largely through their hydrophobic tails, with the sulfonate head relegated to solution (Scheme 2). At the a-Fe 2 O 3 surface, SDS likely has the opposite geometry with the first sorbate layer orienting the hydrophobic tail toward to the solution (Scheme 2).…”