Porod invariant

The Porod invariant, is the integral of the ara of the Kratky curve:

$I_{\mathrm {total} }=\int _{0}^{\infty }I(q)q^{2}\mathrm {d} q$

This quantity is independent of concentration, and is proportional to molecular mass. In principle, one can use this method to measure MW. However, the MWs determined in this way are often inaccurate (incorrect background subtraction, intrinsic flexibility, etc.).

See Also

• Porod scattering