Partial specific volume explained

The partial specific volume

\bar{v _{i},} express the variation of the extensive volume of a mixture in respect to composition of the masses. It is the partial derivative of volume with respect to the mass of the component of interest.V = \sum ^{n} ^{i =1} m _{i} \bar{v _{i},}

where

\bar{v _{i}} is the partial specific volume of a component i defined as:\bar{v _{i}=\left(} (\partial V)/(\partial m _{i}) \right) _{T,P,m _{j ≠}} .

The PSV is usually measured in milliLiters (mL) per gram (g), proteins > 30 kDa can be assumed to have a partial specific volume of 0.708 mL/g.^[1] Experimental determination is possible by measuring the natural frequency of a U-shaped tube filled successively with air, buffer and protein solution.^[2]

Properties

The weighted sum of partial specific volumes of a mixture or solution is an inverse of density of the mixture namely the specific volume of the mixture.

v = \sum _{i} w _{i ⋅} \bar{v _{i}} = (1)/(\rho) \sum _{i} \rho _{i} ⋅ \bar{v _{i}} = 1

See also

• Partial molar property
• Apparent molar property

References

1. Book: Buxbaum . Engelbert . Biophysical Chemistry of Proteins . limited . 2011 . Springer . New York, Dordrecht, Heidelberg, London . 978-1-4419-7250-7 . 237–249 . 25: Centrifugation. 10.1007/978-1-4419-7251-4_25 .
2. Book: Kratky, O. . Leopold, H. . Stabinger, H. . Hirs, C.H.W. . Timasheff, S.N. . Meth. Enzymol. Vol. 27: Enzyme Structure Part D. 1973 . 978-0-12-181890-6 . 98–110 . 5: The determination of the partial specific volume of proteins by the mechanical oscillator technique.