Chromatography Forum

What are the pros/cons of screw vs crimp caps?

What benefit do you see from either?

With electronic tools that crimp and decap for you I wonder who would want to screw all those lids on by hand? Are there benefits I don't know about?

if you need to take a cap on and off a lot during sample prep, then screw-cap is nice. Screw caps are great if you're the sort of facility that expects non-expert co-workers in non-specialist labs to prepare samples in vials (saves everyone having crimping tools). On the other hand, if you're using magnetic sample-handling robotics then magnet-friendly crimp-tops are almost inevitable.

mlhuls01 wrote:
What are the pros/cons of screw vs crimp caps?

What benefit do you see from either?

With electronic tools that crimp and decap for you I wonder who would want to screw all those lids on by hand? Are there benefits I don't know about?

One thing I have noticed with screw caps is that if you use the kind without a pre-cut septum and you tighten the screw cap too tightly, I've seen inconsistent sample injections and I have even seen the auto-sampler needle on our GC actually pick the vial up from the tray because the needle didn't come out properly.

I prefer screw cap, personally just because I'm filling every vial up with a different solution and I can just cap it as I go.

I have found the crimp cap better with an automatic crimper when I'm filling up 50+ vials of the SAME solution and I go through and pipette X amount of volume of the same solution into 50 different vials. Then I can just go in and crimp them all quickly with an automatic crimper.

I think the bigger concern I've always had was how tight I make the screw cap and whether or not the cap came with a pre-cut septum or not.