โ๏ธ Column Loading Calculator
Calculate maximum sample loading capacity or required silica mass for a flash chromatography column.
Frequently asked questions
What silica:sample ratio should I use?
30:1 is a common default for routine separations with reasonable ฮRf between compounds. Use a tighter ratio (10-20:1) for well-separated, easy mixtures, and a looser ratio (50-100:1) when compounds are closely spaced or difficult to separate cleanly.
Does column diameter matter for this calculation?
This calculator works from total silica mass rather than column diameter directly, since silica mass is what most flash chromatography guides and cartridge specifications reference. If you know your column's silica mass (often printed on prepacked cartridges), you can use it directly here.
What happens if I overload the column?
Overloading typically causes peak broadening, tailing, and reduced resolution between the target compound and impurities, since the stationary phase's separating capacity is exceeded relative to the amount of sample applied. If you see poor separation, consider using a higher silica:sample ratio or a larger column.
Accuracy & how this is derived
Derivation: Standard flash chromatography loading heuristic: maximum sample mass equals total silica mass divided by a loading ratio (typically 20:1 to 50:1), chosen based on the difficulty of the separation.
Validated against: Widely used flash chromatography loading guideline consistent with Still, Kahn and Mitra (1978) and common organic chemistry laboratory practice.
โ ๏ธ For educational and research support only โ verify critical results independently before use in regulated, clinical, or publication-bound work.
โ Last updated: July 2026 ยท Report an error
Sample loading capacity in flash chromatography
Flash chromatography column loading capacity is commonly estimated as a simple ratio of silica mass to sample mass, with typical values ranging from 20:1 to 50:1 depending on how closely spaced the target compound's Rf is to nearby impurities. Loading beyond this capacity tends to broaden and tail peaks as the stationary phase's separating power becomes overwhelmed relative to the sample applied, which is why choosing an appropriate ratio upfront โ rather than discovering overload mid-run โ is a standard part of planning a flash purification.