Concealed

[Jennifer L. Potter]

Dear John,

We have (I believe) the older version of the Gene Quant II, the Gene 
Quant.  We use it for both DNA and protein measurements.  As far as I
know, no one in the lab uses the fancy calculator part of the machine.

A few comments that may or may not be pertinent to the Gene Quant II:

The machine is a single beam spec...and therefore has greater variability
at lower absorbances.  For example, I blanked the machine with water and
then tested the exact same sample about 10 times.  The A260 varied 
between -0.01 and +0.01.  Our double beam spec, however, does not deviate
in this manner (I am told this is an intrinsic difference between single 
and double beam specs).  Comparing highly absorbing samples (>1.0) with 
our double beam showed the two readings to be identical.  

As a personal preference, I really don't care for the way the machine
beeps at you to tell you when to insert and remove the cuvette.  If 
you're not alert and focused, you'll be too slow and it will beep at you
again and make you start all over.  Pharmacia people use this,however,
as a selling point because it conserves lamp time.

One other point, our manual did not describe all the different functions 
and how to use them in great detail.  I'd expect the manual for the Gene 
Quant II to be better.

I'm sorry I can't fill you in on more detail about the calculator 
function, etc. but hope I've given you some useful information.  We use 
ours quite frequently and it has held up fine for the 2-3 years we've 
owned it.  The only down side that I see is the variability at low 
absorbances...before I actually tested the same sample 10 times in a row, 
I kept wondering where my DNA went! :)

Best of luck,

Jennifer L. Potter
Medical College of WI
Dept of Biochemistry