Multi-stage mass change

E. J. Chang, V. Archambault, D. T. McLachlin, A. N. Krutchinsky, and B. T. Chait, Analysis of protein phosphorylation by hypothesis-driven multi-stage mass spectrometry, Anal. Chem. 76 (2004), 4472-4483. 

If our main interest is in the total volumetric mass transfer between the liquids, the role of shear rate and blend time is relatively minor. However, if we are interested in the bubble-size distribution, and we often are because that affects the settling time of an emulsion in a multi-stage co-current or counter-current extraction process, then the change in macro- and micro-rates on scale up is a major factor. Blend time and circulation time are usually not a major factor on scale up. 

Multi-layer sorption, on the other hand, would have to involve an interaction between mannan chains themselves. Mannan sorption seems, however, to be built up of two stages firstly, the initial very rapid sorption, followed by a much slower sorption phase, which may be the multilayer sorption (20). A change in the mannan conformation after sorption may perhaps enable or facilitate mannan - mannan interactions and allow multilayer sorption. Studies at our laboratory on sorption of mannans onto bleached kraft pulp (BKP) showed that sorption of a high-molar-mass GM was not affected by the presence of a layer of presorbed low-molar-mass GM, and vice versa (31). Furthermore, sorption onto mechanical pulp fibers, which already contain high amounts of hemicelluloses and probably little, if any free cellulosic surfaces, has also been achieved with certain mannans. This point will be further discussed in the next chapter. 

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