SEC-MALS Service

SEC-MALS Service


SEC-MALS combines size-exclusion chromatography (SEC) with multi-angle static light scattering (MALS) to measure accurate masses of macromolecules. SEC is a well-established tool widely used to measure massed of macromolecules, based on the hydrodynamic volumes and sizes. The elution volume is calibrated against known standards. Therefore, the key of accurate results is the similarity between the unknown molecule and the known standards.  SEC only is not fit for measuring the volumes and sizes of elongated or sticky proteins. MALS measures absolute molar mass and size of the molecules based on the intensity and the angular by scattered light. SEC-MALS generates more accurate mass measurements than that either way alone.

Molar masses for two distinct ADC formulations are determined using SEC-MALS analysis[1].


Protein Amount

50-500 µg

Protein Volumes

20-120 µl (total)


Maximum injection volume: 100 µl

Minimum injection volume: 5 µl

(This should include at least 10 µl above the injection volume for auto sampler dead volume.)


Running Buffers

Most standard aqueous SEC running buffers should be fine.

Make sure you know the buffer compatibility of the SEC column you are using.

Recommended: 25 mM HEPES pH 7-7.5, 150 mM NaCl, 0.02% NaN3 (filtered).



Samples must be filtered or centrifuged prior to injection.

Know the concentration (in mg/ml) of your protein.

Know the UV extinction coefficient in mL/mg•cm.



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