Chromatography Forum

Hi everyone,

I'm setting two GC's in my lab, namely a GC/FID (HP5890) and GC-MS (HP5890/5972). Does anyone have any recommendations on a vendors for copper tubing (1/8"), tubing cutters, etc.?

I know Restek has all this, but just wondering if there were others less known vendors out there.

I'm assuming I should only use brass fittings to connect my copper lines. I'm not sure if there are any issues (ie. galvanic corrosion) with using stainless steel fittings on copper?

Thanks so much.

lespaul wrote:
...I know Restek has all this, but just wondering if there were others less known vendors out there.
...

Is Sigma Aldrich less known than Restek ?

We used Restek and Supelco for GC stainless steel and copper tubing, and tools and connectors. SwageLok fittings can also be purchased from their vendors.

I'd match up ferrules and tubing best I could: SS with SS, and brass ferrules and unions/tees with copper tubing.

I'd like to add that SwageLok fittings are not the only ones suitable for your installation.
You may as well use Hoke Gyrolok or Parker A-lok.
Here is an excerpt from Parker fitting catalog:
"In addition, Parker instrument fittings are designed to work on like materials. Stainless steel fittings should be
used only with stainless steel tubing, aluminum fittings with aluminum tubing, etc. The practice of mixing materials
is strongly discouraged. The only exception is brass fittings with copper tubing.
Dissimilar materials in contact may be susceptible to galvanic corrosion. Further, different materials have different
levels of hardness, and can adversely affect the fittings ability to seal on the tubing."

dblux_ wrote:
I'd like to add that SwageLok fittings are not the only ones suitable for your installation.
You may as well use Hoke Gyrolok or Parker A-lok.
Here is an excerpt from Parker fitting catalog:
"In addition, Parker instrument fittings are designed to work on like materials. Stainless steel fittings should be
used only with stainless steel tubing, aluminum fittings with aluminum tubing, etc. The practice of mixing materials
is strongly discouraged. The only exception is brass fittings with copper tubing.
Dissimilar materials in contact may be susceptible to galvanic corrosion. Further, different materials have different
levels of hardness, and can adversely affect the fittings ability to seal on the tubing."

I definitely would avoid aluminum mixed with any other metal, but we have never had problems mixing stainless steel and copper, it is done with electrical fittings all the time. Of course electrical codes also prohibit mixing aluminum with copper or stainless steel.

Restek is where we always get our tubing, simply because they offer the pre-cleaned for GC use tubing. When I first began working in the lab they bought the tubing from the local A/C repair shop but we had to flush it wish a lot of methylene chloride and hexane and flow nitrogen through it while baking it in the oven over night, so pre-cleaned is definitely worth it.

Ohio Valley Specialty Company selling precleaned copper tubing and swagelok fittings.

Not sure if they're still around, but I've had good experiences w/ both Optimize Technologies and Upchurch Scientific.

Thanks everyone!! I'll check them all out.

DR wrote:
Not sure if they're still around, but I've had good experiences w/ both Optimize Technologies and Upchurch Scientific.

I believe Upchurch was bought by IDEXX but you can still get the items through them. Get most of my HPLC fittings from Upchurch.

I believe Upchurch was bought by IDEXX

Correct, but I think it's IDEX. IDEXX and IDEX are different companies.

We buy a lot from Restek. Establish a contact with your salesperson. Ours is great - do get quotes on your larger purchases to save money.

Used to be a fan of Supelco long ago, but not now. The final incident for me was during an instrument install, using a brand-new, sealed box of their 1/8" GC tubing, while I was working with it, liquid began dripping out! Yikes. Presumable residual solvent from what they rinse the tubing with, but was really surprised. Never problems with Restek tubing, or anything else for that matter.

Jake wrote:

I believe Upchurch was bought by IDEXX

Correct, but I think it's IDEX. IDEXX and IDEX are different companies.

We buy a lot from Restek. Establish a contact with your salesperson. Ours is great - do get quotes on your larger purchases to save money.

Used to be a fan of Supelco long ago, but not now. The final incident for me was during an instrument install, using a brand-new, sealed box of their 1/8" GC tubing, while I was working with it, liquid began dripping out! Yikes. Presumable residual solvent from what they rinse the tubing with, but was really surprised. Never problems with Restek tubing, or anything else for that matter.

Yea I can never remember if it is one or two X.

Supelco was bought by Sigma Aldrich which has been bought by Millipore. Seems each time one of these big companies gets bought by a bigger one it is rarely an improvement. Sometimes it is, but not always.