Tropix pulls off a STING

Paul N Hengen pnh at ncifcrf.gov
Tue Oct 24 14:49:58 EST 1995


*** Warning: Tropix switches membranes without telling researchers ***

Here is a warning to all those who have been using the Tropix Chemiluminescent
detection kit called Southern Light. Although I have given this kit high marks
for more than a year, I have recently made a horrible discovery about the
transfer membrane supplied with the kit (Tropilon Plus). I bought this kit a
year ago and optimized conditions for a series of gel shift experiments using
the Tropilon Plus positively charged membrane. Recently, I had to buy a new kit
and when I switched over to using it, I got big blobs on my X-ray film instead
of nice tight bands. From the looks of it, the DNA did not transfer properly by
using a Hoefer semi-dry blotter that worked before, with partial bands and
smears showing up all over. When I called Tropix to complain, they told me that
they had to change suppliers of the membrane and that the new kit had a
completely different membrane supplied with it, BUT they still call it
Troplin-Plus....NOT Fair I say. If they are to switch membranes and not tell
people who use their kit, AND still call it the same name, this will cause all
sorts of problems like I had. The new membrane did not work. They would not tell
me who was the old supplier, nor the new supplier. When I switched back to the
older style membrane, everything worked great again. If anyone knows who the old
supplier is, I'll gladly change to that membrane.

In addition to pulling the rug out from me, it seems Tropix is continuing to
advertise the Tropilon Plus membrane with literature developed with the older
membrane, showing side-by-side comparisons of blots done with several brands of
membranes. Which menbrane was used in the comparison is a matter of guesswork.
If it is the older one, maybe Tropix should discontinue their claims as well as
their membrane.

*******************************************************************************
* Paul N. Hengen, Ph.D.                           /--------------------------/*
* National Cancer Institute                       |Internet: pnh at ncifcrf.gov |*
* Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |*
* Frederick Cancer Research and Development Center|     FAX: (301) 846-5598  |*
* Frederick, Maryland 21702-1201 USA              /--------------------------/*
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