Effect of Organic Concentration

This may be of importance in membrane filtration, where significant changes in concentration may take place in the boundary layer, where molecular conformation may influence gel layer permeability. However it may only be relevant for feeds of high NOM, high recovery and significant concentration polarisation. 

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Figure 4.6 Effect of organic concentration on retention. (Reproduced from M.W. Dong, J.R. Gant, and B.R. Larsen, BioChromatography, 4 19 [1989]. With permission from Eaton Publishing.)...

Figure 8-9. Effect of organic concentration of diluent on peak distortion.

Figure 6.8 Effect of organic concentration on DOC rejection (15 mgE NOM concentrate, 20 mM NaCl, pH 7).

Fig. 6.3.6 Effects of salt concentration (left panel) and pH (right panel) on the initial light intensity emitted from the homogenate of the Symplectoteuthis oualaniensis light organ. The salt effect was tested in 50 mM Tris-HCl, pH 7.2, and the pH effect in the various buffers containing 0.5MKC1 or NaCl. From Tsuji and Leisman, 1981.

Mathew and Pillai observed a threefold increase in plutonium concentration at low, normal, and high carbonate concentrations when 20mg/liter of organic matter were added to sea water samples (29). Again this indicates the effect of organic complexation upon plutonium solubility in natural waters. 

Greenwood DJ. The effect of oxygen concentration on the decomposition of organic materials in soil. Plant Soil. 1961 14 360-376. 

Acetonitrile, methanol and DMSO had no apparent effect on umbelliferone glucuronidation in human hepatocytes at concentration up to 2% [32]. With HLMs or expressed UGTs, inhibitory effects of organic solvents on glucuronidation of 7-hydroxy-4-trifluoromethyl-coumarin (7-HFC) and estradiol generally followed the order acetonitrile > ethanol > methonal > DMSO [33], DMSO did not inhibit estradiol-3-glucuronidation activity at a concentration up... 

The effects of organic molecules and phosphate on the adsorption of acid phosphatase on various minerals, and kaolinite in particular, have been investigated by Huang et al. [97]. The Langmuir affinity constant for AcP adsorption by kaolinite follows the series tartrate (K — 97.8) > phosphate (K= 48.6) > oxalate (K — 35.6) > acetate (K= 13.4). At low concentration, acetate even promoted the adsorption of acid phosphatase. It was considered that competitive interactions between anionic adsorbates can occur directly through competition for surface sites and indirectly through effects of anion adsorption on the surface charge and protonation. 

Particulate matter concentration, organic content and granulometry For the different types of surfactant, the effect of solids concentration on sorption is unclear. While some studies have shown that the concentration of solids has no effect on the extent of sorption [19,36], in others, it has been detected that the partition coefficient decreases with particle concentration [17,27,37,38]. 

The effects of trace concentrations of dissolved organic matter and of orthophosphates (Berner and Morse, 1974) and polyphosphates as "crystal poisons" (e.g., inhibiting the spread of monomolecular steps on the crystal surface by becoming... 

Figure 4.5 Effect of organic modifier on peptide retention. Synthetic octapeptides of the structure described in Figure 4.1 were separated by gradient elution on an octyl column using aqueous-organic systems containing a constant TFA concentration of 0.1%. (Reproduced from D. Guo, C.T. Mant, A.K. Taneja, J.M.R. Parker, and R.S. Hodges, J. Chro-matogr., 359 499 [1986]. With permission from Elsevier Science.)...

Few reports are available on the potential effect of chemical concentration on the BAF in an aquatic organism (e.g., Mayer, 1976). Yet, a key assumption of EP theory is the independency of BAF relative to exposure concentration. To our knowledge, there is only one report (Huckins et al., 2004) in the peer-reviewed literature, where the effect of chemical exposure level on concentration factors (CFs) or BAFs has been tested in side-by-side BMO and passive sampler exposures. Huckins et al. (2004) defined CF as the ratio of the concentration in a sample matrix (whole body [soft tissues in the case of bivalves] or whole SPMDs) relative to the concentration in the ambient exposure medium at any moment in time, whereas the A sw and BAF (includes biomagnilication) represent the maximal CF. Similar to ATs s and BAFs, CFs are expected to be independent of exposure concentrations, when residue exchange follows first-order kinetics. 

Wang, Y.-S., Subba-Rao, R.V., and Alexander, M. Effect of substrate concentration and organic and inorganic compounds on the occurrence and rate of mineralization and cometabolism, Appl. Environ. Microbiol, 47(6) 1195-1200, 1984. 

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