pI determination methods for QC

StewJW via methods%40net.bio.net (by stewjw from gmail.com)
Tue Jan 20 05:11:04 EST 2009


Invitrogen do offer the precast Novex IEF gels which are used in their
standard Surelock appararatus but they range from pH 3-10 or pH 3-7.
For crude estimation there are also IEF markers in the 3.5 - 10.7
range.

The IPG (immobiliased pH gradient strips) Runner system you mentioned
is designed for running 2D gels of a large number of samples. There is
a gel strip holder, IPGRunner Cassette, which fits inside the
Invitrogen Surelock mini-gel apparatus. Each cassette can hold upto 6
(7cm) strips. The strips come in the following pH ranges:

ZOOM® Strips pH 3-10NL 12 ZM0011
ZOOM® Strips pH 4-7 12 ZM0012
ZOOM® Strips pH 6-10 12 ZM0013
ZOOM® Strips pH 4.5-5.5 12 ZM0014
ZOOM® Strips pH 5.3-6.3 12 ZM0015
ZOOM® Strips pH 6.1-7.1

After running the IEF strips they are individually removed and placed
long ways inside an insert of a precast ZOOM® Gels, which are  are 8 x
8 cm, 1.0 mm thick pre-cast polyacrylamide gels to run the second
dimension.

http://tools.invitrogen.com/Content/SFS/ProductNotes/F_071215_ZOOM%20IPG%20Runner-MKT-RD-TL-HL.pdf
http://tools.invitrogen.com/content/sfs/manuals/zoomipgrunner_man.pdf

I've never used this, and I'm unsure how practical it is to excise
small samples from gels to measure their pH in solution. Thermo-
Russell sells a small Ag/AgCl combination electrode which can measure
down to 50µl of liquid, catalogue number: CMAW711/4/5/SC; dimensions
below cap are 90mm x 5.5mm. See www.thermo.com/russell. I should say I
work for Fisher UK a ThermoFisher company so I'm a little biased in my
recommendation.





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