Nov 18, 20221 min read

Microns to kDa (Kilo Daltons)

What is the relationship between kiloDaltons and Microns?

Many people have the above question in their minds. There is a fundamental difference between kDa and Microns..

kDa is an unit of molecular size, while, Microns is an unit of distance or in other words molecular diameter.

When the kDa of a molecule rises this means that the number of atoms in the molecule is rising. See below picture for an example where the increase in number of atoms implies an increase in kDa value of that molecule.

How Molecular Weight Does not affect Diameter of molecule necessarily — Microns to kDa_Theway Membranes

But, just as seen above. even if there is an increase of 66% of atoms, and thereby 66% increase in kDa value, the effective diameter of the molecule has not increased.

This means if a membrane with a pore size slightly larger than the molecular diameter of the first molecule is used to filter feed liquid consisting all three molecules above, then all of the three molecules will pass across the membrane.

As elucidated above, one cannot arrive at a direct relationship between kDa and Microns. Always get your membranes from manufacturers who are willing to divulge pore size in microns instead of just kDa.