[RASMB] (no subject)

[Ewa Folta-Stogniew]

John, I do not have experience with CD at all, but I
maintain a stopped-flow spec from Applied
Photophysics, which I am not that happy with.  In
particular, I do not like their support and their
warranty/service policies.  For example, we had a
failure of one of the valves during warranty period
for which AP charged us over $600 in replacement since
they claimed this was wear and tear of the instrument
which the warranty did not cover (???).
Also, the operating system on which the instrument
runs is the AP's "acorn" system which is not that user
friendly at all.  

There is no technical service in States and for all
repairs the instrument (or pieces of it) need to be
shopped via FedEx to UK, which is a real hustle
recently with all the extra security for international
shipments (not mentioning the costs).

Ewa



--- John Burgner <jwb at bilbo.bio.purdue.edu> wrote:

>
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> 
> 
> Dear All,
> 
> Does anyone with recent experience with "state of
> the art" CD spectrometers
> have strong feelings on which  instruments would
> best fulfill the
> description given below. 
> Based on an intial investigation, it lookes like
> both  the Aviv 215 and the
> Jassco J-810 fit the bill. Both Olis and Applied
> Photophysics seem to be
> close 
> 
> 
> Based on a survey of proven and potential users,
> high-quality sample
> temperature control with automatic temperature
> ramping is an absolute
> requirement for all.  A rapid stopped flow system
> (less than or equal to 1
> ms dead time) is also essential for several users
> and will provide the fast
> kinetic circular dichroism capabilities that are
> currently absent from
> campus.  An automatic microtitrator will eliminate
> tedious and error-prone
> manipulations and provide for time-saving automated
> data collection.  This
> last capability was requested by several users,
> particularly for ligand
> binding studies and the determination of protein and
> nucleic acid stability
> as a function of denaturant concentrations. 
> Automatic titration will also
> require a device for the effective mixing of sample
> and titrant in the
> cuvette.
> 
> An additional optics and data processing package to
> allow the detection of
> fluorescence polarization and anisotropy in the same
> instrument would be a
> very valuable addition.  This polarization and
> anisotropy capability is not
> replicated anywhere else on campus.  Since these
> packages also allow
> collection of total fluorescence emission, this
> addition would enhance the
> current fluorescence stopped flow capabilities on
> campus.  The fluorescence
> package will allow simultaneous collection of
> circular dichroism and
> fluorescence signals on the same sample, providing
> immediate confirmatory
> data and reducing sample preparation requirements. 
> When combined with the
> proposed automatic titrator, this package would
> enable stability and ligand
> binding studies by complementary methods on samples
> in precisely the same
> state (e.g. same ligand and/or denaturant
> concentration).  
> 
> Thanks for your help
> John
> 
> John W. Burgner
> Department of Biological Sciences
> Purdue University
> 915 West State St
> West Lafayette, IN 47907-2054
> 765-494-4960
> 765-496-1189 (fax) 
> 
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