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Choosing the Right EXP Fitting


There are many different types of fittings for making connections with liquid chromatography. We recommend using EXP fittings when working with stainless steel tubing. They are reusable and available in a number of configurations, so you get exactly the type of connection you need throughout your system. We’ll show you how to select the right one every time.

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Hi, everyone. Thanks for joining us for this Restek Tip. Our topic today is EXP fitting selection. Now, the EXP system is for stainless steel tubing, and it's got several different types of nuts along with the PEEK and titanium hybrid ferrule. Now, the way the ferrule works is that the PEEK portion goes into your column port and makes the seal while the metal portion faces the nut so when tightened the ferrule securely grips the tubing without permanently attaching. So, it can be reused multiple times without compromising the seal. You have a few choices when it comes to the style of nut.

First is the traditional hex head in three different lengths of the threaded shaft. This could be an all-purpose connection for a pump outlet to the mixer tubing or for the connection to the mixer itself. Next is the hand-tight fitting, which has a little bit of a larger head for better grip when you're tightening by hand. You need to use this where you have a little extra space, like a connection from the pump to the mixer. Finally, there's the EXP2 style, which is a slim head and comes with a nut driver, so you're able to install the fitting in a space where it's a little tight squeeze, like on a multiport valve. No matter which one of these fittings you choose, you're ensured to have a reliable connection for your LC tubing.

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