ASK BEN | How to Choose an HPLC or GC Syringe
Syringes are an essential part of HPLC and GC systems. In order to analyze a sample mixture on an LC column or GC column, the sample must be introduced into the flow path, and syringes make that possible. For this reason, syringes are often found in the drawers of standard laboratories. However, choosing the right syringe for your application can cause some uncertainty. I’ve had many customers come to me unsure of what syringe they should use, unaware of what options there are.
"Choosing the right syringe for your application can cause some uncertainty. I’ve had many customers come to me unsure of what syringe they should use, unaware of what options there are."
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:
- Beveled – mainly used for GC when you need to pierce a septum
- Blunt – often times used for HPLC injections, TLC, or general liquid handling
- Conical with a side port – generally used for headspace GC applications, or anything prone to needle clogging
- Conical non-coring – typically used for autosampler injection and pre-pierced septa
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).
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.
About the Author
Ben graduated from University of St. Thomas in 2019 with a BS in biochemistry. He joined the Chrom Tech team last year, and has been a great asset to our sales/support team! Outside of work, Ben enjoys spending time grilling and socializing with friends, and always seems to make time to get in a workout! If you have a question you'd like Ben to answer in the blog, email Ben at email@example.com.