That being said, in-line SEC-DLS-SLS etc is a much more powerful technique, but is less straight-forward, has a larger footprint and as has been mentioned, less-inexpensive.
Having an online SLS (or MALLS as people call it as well these days, multi angle laser light scattering ) is indeed nice, and clearly useful for assessing real molecular weights.
Having an online DLS (which basically is more or less the same instrument but just capable to do an auto-correlation of the scattering signal over time from what I know) somehow misses the point (or do I miss the point?): a. you want to do DLS to check polydispersity of your ready-to- crystallize sample in various buffers, thus why online? 96-well format is more like it. b. if you do online DLS you need to autocorrelate the signal over a few seconds, so you loose some of the resolution in your SEC/SLS profile? I admit however that I am not sure how long you need to autocorrelate the scattered intensity to evaluate if you have a single exponential decay that would suggest a mono-disperse particle
We have looked at the possibility of one instrument doing Static, On- line LS *and* DLS in a cuvette. Given that the MALLS is quite a sensitive do-not-disturb-me kind of beast, I feel better we did not do that.
Tassos
