[RASMB] Help

[Arthur Rowe]

Dear Gouzhou

This must be the world's (or at least RASMB's) simplest suggestion on offer.
Why not simply measure the density ? OK - you do not have a digital density
meter to hand, I presume. But surely you have a decent 4-place balance
around ? Just dispense 1 ml of fresh distilled water carefully into it
beaker several times, note the weight each time, take the average. And then
without changing pipette or tip rinse the tip with HEPES once into the sink
and then repeat the process of dispense, weigh, then average. Divide
average(2) by average(1) and you have the relative density of HEPES. Find
the density of water at whatever temperature you have worked at, and you can
convert to absolute density.

So - the value will not be as accurate as using a DDM. But for sedimentation
work, it will be fine. And it will only take you a few minutes to do.

All best

Arthur R owe

--
*******************************************************
Arthur J Rowe
Professor of Biomolecular Technology
NCMH Business Centre
University of Nottingham
School of Biosciences
Sutton Bonington
Leicestershire LE12 5RD   UK

Tel:        +44 (0)115 951 6156
            +44 (0)116 271 4502
Fax:        +44 (0)115 951 6157
email:      arthur.rowe at nottingham.ac.uk
            arthur.rowe at connectfree.co.uk (home)
Web:        www.nottingham.ac.uk/ncmh/business
*******************************************************




Hi, 
I am using analytical ultracentrifugation to study my protein. I need
calculate the solvent density of HEPES which is not listed in BECKMAN
manual. Does anyone have the parameter for HEPES? Thanks a lot!

Best regards,
 
Guozhou Chen          mailto:gchen at bio.indiana.edu
========================================================
Biology Department, Indiana University
(Home) 812-336-4099, (Lab) 812-856-0249
(Lab) http://sunflower.bio.indiana.edu/~lingchen/lab
(Personal) http://bio.indiana.edu/~gchen/main.htm
========================================================


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