What is the best way to get an optimal seal from autosampler vial screw caps?

The “best practices” for applying autosampler vial, screw caps is not to “tighten them down” as much as possible. In fact, this is contra-indicated as it will cause the septa to “dimple” creating “peaks and valleys” instead of sealing, smoothly against the glass or plastic vial rim.  

You want to make sure that the seal is even across the entire septa / vial after screwing the cap on the vial and with strong enough downward pressure from the cap. This will ensure that the cap does not “back off” and leak.

The best practice for the best seal is to screw the cap on the vial until snug. Then simply twist the screw cap just another 1/8th of a turn.

Click HERE for video instructions on how to properly screw on screw caps for the optimal seal.

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