Methanol/acetonitrile eluent mixture viscosity

The viscosity of water/organic mixtures should be considered as an additional parameter in the selection of organic modifier. Acetonitrile/water mixtures show roughly 2.5 times lower viscosity than equivalent methanol/water eluents this means that one can use 2.5 faster flow rates with acetonitrile as organic modifier and develop faster separation methods. 

FIGURE 13.2 Plots of viscosity versus eluent composition for binary mixtures of water and methanol (top curve) and water and acetonitrile (bottom curve). 

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