Hi Tommi - I find it to be very stable day-to-day. However, the alignment between UV, RI and light scattering can be very misleading depending on the size of the particle you're analyzing (and of course, that makes all the difference in the world in getting an accurate result). I find that very large things will have a scattering profile that doesn't align well at all with the UV and RI. What I usually do is use the alignment parameters from a small, more isotropic scatterer like cytochrome C or RNase A at high concentration for my experimental runs.
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:CCP4BB@JISCMAIL.AC.UK] On Behalf Of tommi kajander Sent: Friday, February 18, 2011 9:08 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] MALLS analysis question Hi, if you happen to have Wyatt's light scattering detector + their RI detector rEX, together with analytical HPLC/SEC system what are your experiences on the stability of the aligment? the digital connections dont seem to work for us. ie. apparently synchronizing the signals from different detectors (computers) to the analysis software computer dont work, even if the alignment (ie delay volumes between detectors) has been done. Should work with analog cables to one detector and then LAN connection from there on to the analysis PC. testing it.quit certain it will. but i would be happy to hear if anyone had similar problems.... Thanks! 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: Viikinkaari 1, 4th floor) University of Helsinki FIN-00014 Helsinki, Finland Tel. +358-9-191 58903 Fax +358-9-191 59940
