Hi Tommy, While I cannot comment on the Viscotek or Varian/Agilent products, I can say a few things about the Wyatt product:
We have a Dawn Heleos II 18-angle instrument with inline QELS here in the lab along with one of their older Optilab RI instruments. We use TSK columns for protein characterizations and GE S200-like columns for protein-nucleic acid complexes. We've had the set-up for about 18 months now, and we're very happy with the product. It's become a routine-use instrument in the lab for the characterization of protein and protein-nucleic acid preparations that are about to go into crystal trials and SAXS experiments. If used properly, the accuracy and reproducibility of the mass determinations for protein samples are very good - usually within a few percent of actual mass and about as good as what I would get from an AUC sedimentation equilibrium experiment. (This becomes a trickier issue with composite particles like protein-DNA, as you have to implement a mass-averaged dn/dc figure and so on) We've used it successfully on systems where the particles range from 12 kD to upwards of 660 kD. The customer technical support is good, too. Hope this helps, Kushol Kushol Gupta, Ph.D. Research Associate Van Duyne Laboratory - HHMI/Univ. of Pennsylvania School of Medicine kgu...@mail.med.upenn.edu 215-573-7260 / 267-259-0082 -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Tommi Kajander Sent: Sunday, June 20, 2010 7:28 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] LS / RI detector systems Dear All, I would like to ask people's comments on usage/preferences on different providers MALLS/RALS detectors and RI detectors (to combine with HPLC SEC) Mainly we are looking at Wyatt vs Viscotek (or perhaps Varian/Agilent now also) tetradetektors(or triple) detectors at the moment, i am not aware of many other options.. In particular what is your take on Wyatt MALSS accuracy *(why bother with several angles???? although i kind of like the software and instrument...) vs RALS for proteins (which end up being angle independent in scattering anyhow) --or what do you think overall of the different manufacturers equipments accuracy, etc... e.g. viscometer seems rather unnessary to me, as does online DLs.. Thanks for comments, Tommi -- Tommi Kajander, Ph.D., Docent Macromolecular X-ray Crystallography Research Program in Structural Biology and Biophysics Institute of Biotechnology P.O. Box 65 (Street address: Viikinkaari 1, 4th floor) University of Helsinki FIN-00014 Helsinki, Finland Tel. +358-9-191 58903 Fax +358-9-191 59940
