Historians believe that in newspost <[email protected]> on Fri,
19 Apr 2013, DK <[email protected]> penned the following
literary masterpiece:
Another opinion, perfectly
reasonable, is that the kind of tubes one uses really matters.
What tubes do you use? I used the ones that worked really well
on 2720 model and I don't think that they are made of polypropylene,
for example. PE/ABI claim that plasticware requirements for 9700
and 2700 series are identical. My problem stems from the fact that
this is most definitely not the case. (Or I am having a bad dream).
We use what used to be ABgene tubes, now part of Thermofisher.
104C is pretty standard for a heated lid.
Really? I thought 100C is the standard. But I really don't have experience
with that many cyclers. Good to know it's not a fundamental problem.
It's not going to really matter. Polypropylene melts a long way above
that so anything approx. will do.
DK how are you determining overshoot, measurement by thermocouple in a
tube or watching the temp. The displayed temp is block temp and not tube
temp which, will always lag behind.
In the initial testing, I stuck a thermocouple wire betwen a block and a
thin-walled tube jammed in place. *Looked* accurate enough and
of course I am not about to buy $2000 calibration kit (which just might
to be the same thing...)
The problem with the thermocouple is that it will be measuring block
temperature and not the in tube temperature. There will be at least a
0.5C difference. Just as difficult measuring in the tube because the
sheer mass of even a tiny thermocouple will pull heat out of the small
volume in the tube.
A multiplex PCR across all wells and run out on an agarose gel is pretty
good at testing consistency across a block. Overshoot or undershoot
isn't usually too much of an issue providing it is consistent across the
whole block. I don't want a PCR working in the middle of a block and
failing at all the edges!
Duncan
--
I love deadlines. I especially like the whooshing noise they make as
they go flying by.
Duncan Clark
GeneSys Ltd.
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