ASK BEN | How to Choose an HPLC or GC Syringe

Syringes play a crucial role in HPLC and GC systems. To analyze a sample mixture on an LC or GC column, the sample must be introduced into the flow path, and syringes make this possible. As a result, syringes are commonly found in the drawers of most laboratories. However, selecting the appropriate syringe for your specific application can be confusing. Many customers have approached me unsure of which syringe to use, unaware of the various options available.

Where to start...

When choosing an HPLC or GC syringe, you need to consider the syringe type, point style, gauge, and termination. The most common types of syringes for analytical (chromatography) purposes are microliter and gastight. You’ll typically only see microliter syringes used for HPLC, whereas gastight syringes are used for both GC and HPLC. Gastight syringes have an inert PTFE plunger tip that creates a gastight seal, so they’re ideal for long dispense times, heterogeneous solutions, or viscous liquids.

Which point style do you need?

There are four different point styles to syringe needles:

1. Beveled – mainly used for GC when you need to pierce a septum
2. Blunt – often times used for HPLC injections, TLC, or general liquid handling
3. Conical with a side port – generally used for headspace GC applications, or anything prone to needle clogging
4. Conical non-coring – typically used for autosampler injection and pre-pierced sept
   

Needle gauge

The needle gauge is dependent on what size needle you need. The gauge is the inverse of its size (smaller needles have a larger gauge, larger needles have a smaller gauge).

Syringe Terminations

The different syringe terminations all have a specific purpose. Cemented needles are for low-volume syringes, while luer tips are generally for mid-volume syringes and are removable. Knurled hub terminations are for modified microliter syringes. Fixed needles are found on CTC syringes. There are many others to speak of with different purposes (PTFE Luer Lock, Fixed Needle, SampleLock, Bubble Free, etc.), the list goes on.

How can we help?

To sum up, if you’re using an HPLC you could use either a microliter or a gastight syringe, but if you’re using a GC then you’ll want a gastight syringe. The needle point style and syringe terminations make a very large difference in the functionality of the syringe. If you don’t know specifically what type of syringe you’ll need for your application, feel free to give us a call or contact our support email. We would be more than happy to help.