Hello,
I am having great difficulty locating a particular type of screw-top
vial cap.

What I want is a solid (i.e. no septum hole) phenolic cap with a teflon
liner backed with silicone rubber. These must fit Chromacol 2-SV
screw-cap vials. I need this type of cap for micro-derivitization
reactions that require a good seal under moderate heat and pressure.

Currently, I use Supelco (p/n 33242) phenolic caps that have a
teflon-faced silicone liner, but unfortunately also have a septum hole,
which means that my samples are frequently lost because the liner
ruptures through the septum hole when the vial contents are heated. I
have also tried Chromacol 8-SC-S115 caps, which are of a similar design,
but actually rupture even more readily than the Supelco caps.

I cannot use solid caps that have a PTFE liner alone, because an
imperfect seal is made with the vial. They must therefore be backed
with silicone or some other material.

I would appreciate any suggestions in locating a supplier for vial caps that would suit
my purpose - even if this meant purcahsing separate caps and liners that
I could assemble myself.

thanks
Tony

Wheaton produce solid caps for 2 ml vials with 8-425 thread.
internet adress : www.wheatonsci.com

http://www.mgscientific.com/store/department.asp?DEPARTMENT_ID=329

http://www.mgscientific.com/store/department.asp?DEPARTMENT_ID=192