my experience with Biorad posphoimager GS250

the End jgraham at
Thu Oct 7 10:07:50 EST 1993

We have been using the Molecular Dynamics Phosphoimager here in the 
Biochemistry section of the Chemistry Department for about two years now
without any significant technical problems. Runs on a 486 Pee-Cee. The 
company claims six order of magnitude accuracy in quantitation. It also 
requires spotting of known label to give cpm, and does not indicate the 
length of exposure. Sensitivity is simillar to autoradiography, in that
the image looks simillar, with larger background usually from the imager.
The only "sensitivity" difference is that hot gels can be exposed for 
short periods (1-2 h) and give similar results to overnight autorads, and 
you can adjust the pixel representation, in order to "bring out" weak
bands. This can sometimes allow reading of DNA sequence information that
is too unclear to be seen in autoradiography.

Because of the accuracy of quantitation and the reduced expense of film
images, I consider phosphimaging a major advance in standard practices.

J. Graham
Indiana University Bloomington

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