Lumatix
Tools

Chromatography calculators

Small, free tools for the numbers you need every day in downstream process development. Everything runs in your browser.

Time and residence time are the same question, twice

A chromatography step is a sequence of volumes pushed through a bed at a flow rate. Divide the bed volume by the flow rate and you get the residence time — how long a volume element spends in the medium. Add up the volumes and divide by the same flow rate and you get the cycle time — how long the step occupies the system. One number matters to the molecule, the other to the schedule, and both come from the same two inputs.

The difference between formats shows up in exactly that pair. In a porous bead the target reaches the binding sites by diffusion, so shortening the residence time costs capacity. In a convective medium such as a monolith the flow carries the target past the ligand: MonoCore™ capsules are run at 5 to 10 monolith volumes per minute, a residence time of seconds rather than minutes. Whether that is worth anything depends on whether time is what constrains you.

Both tools run entirely in your browser. Nothing you type is uploaded, and there is no account.

Frequently asked questions

Which tool do I need?

If you are setting or converting a single flow rate, use the residence time calculator. If you want to know how long a whole method takes — or how much of the day a capture step costs — use the run planner, which times every step from equilibration to re-equilibration.

What is the difference between CV and MV?

A column volume (CV) is the volume of a packed bed; a monolith volume (MV) is the volume of a monolith. They are the same idea on different beds, so a method written in column volumes transfers to a capsule as the same number of monolith volumes. On MonoCore™ capsules one MV is 1.8 mL or 5.4 mL depending on the format.

Do the tools apply to packed columns too?

Yes — both are built around the column case and show the capsule beside it for comparison. The residence time calculator also converts linear velocity in cm/h to a volumetric flow rate and back, which applies to a cylindrical packed bed rather than to a capsule.

Why is there no binding capacity calculator?

Because dynamic binding capacity is usually a figure you read rather than one you measure — the manufacturer determines it, and you work with the value under the conditions it was measured at. What that number means, and when it is worth measuring on your own feed, is set out in how to read a dynamic binding capacity figure.

Is my data stored?

No. Both tools calculate in the browser; there is no upload and no account.