7th Oct 2025
ASK BEN | How to Choose an HPLC or GC Syringe
Syringes are essential tools in both HPLC and GC systems. To analyze a sample on a liquid or gas chromatography column, the sample must be accurately introduced into the flow path—this is the syringe’s role. Chrom Tech provides a broad selection of HPLC and GC syringes from leading manufacturers such as Hamilton, Agilent, and Trajan SGE.
Where to Start
When selecting an HPLC or GC syringe, consider these four factors: syringe type, point style, needle gauge, and termination.
The two primary syringe types used in chromatography are microliter and gastight. Microliter syringes are typically used for HPLC applications, while gastight syringes work in both GC and HPLC due to their PTFE plunger tips, which create a leak-free seal.
Choosing the Right Point Style
There are four common syringe needle point styles used in chromatography:
- Beveled – Ideal for GC septum piercing.
- Blunt – Common for HPLC injections, TLC, and general liquid handling.
- Conical with side port – Suited for headspace GC and clog-prone applications.
- Conical non-coring – Designed for autosampler injections and pre-pierced septa.
Point Style Reference Table
| Point Style | Image | Description | Common Application |
|---|---|---|---|
| 2 |  |
10–12° sharp, beveled, curved | Gas chromatography, septum piercing |
| 3 |  |
Blunt, electro-polished tip | HPLC injection, TLC, liquid handling |
| 5 |  |
Conical with side port | Headspace, clog prevention, minimal septum damage |
| AS |  |
Conical, non-coring, durable design | Autosampler injections, pre-pierced septa |
Understanding Needle Gauge
Needle gauge describes the outer diameter (OD) of the syringe needle. Smaller diameters correspond to higher gauge numbers. An “s” suffix (e.g., 26s) indicates a stronger wall for increased durability and reduced bending.
Common Chromatography Needle Gauges
| Gauge | OD (mm) | ID (mm) | Wall Thickness (mm) |
|---|---|---|---|
| 26s | 0.474 | 0.127 | 0.178 |
| 26 | 0.464 | 0.26 | 0.102 |
| 25s | 0.515 | 0.26 | 0.127 |
| 25 | 0.515 | 0.26 | 0.127 |
| 24 | 0.566 | 0.311 | 0.127 |
| 23s | 0.642 | 0.116 | 0.267 |
| 23 | 0.642 | 0.337 | 0.152 |
| 22s | 0.718 | 0.168 | 0.279 |
| 22 | 0.718 | 0.413 | 0.152 |
Syringe Terminations
Different syringe terminations suit different applications. Cemented needles are common for low-volume syringes, while removable Luer tips are best for mid-volume use. Knurled hubs provide a secure grip on modified microliter syringes, and fixed needles are used in CTC autosampler models. Other available options include PTFE Luer Lock, SampleLock, and Bubble-Free designs.
Frequently Asked Questions
Which syringe type should I use for my application?
Use microliter syringes for HPLC and gastight syringes for GC. Gastight models prevent leaks and maintain pressure, while microliter syringes are ideal for precise liquid injections.
What is the difference between microliter and gastight syringes?
Microliter syringes use a finely machined metal plunger and are best for non-volatile liquids. Gastight syringes include a PTFE plunger tip for sealing volatile or gaseous samples in both GC and HPLC systems.
How do I choose the correct needle gauge?
Higher gauge numbers mean thinner needles. For most chromatography injections, 26- to 23-gauge needles are common. An “s” suffix (for example, 26s) indicates a stronger, thick-wall version for greater durability.
When should I use a beveled vs. blunt needle point?
Beveled points are best for GC septum piercing, while blunt or conical points are used for HPLC and liquid handling. Conical side-port needles help reduce clogging in headspace analysis.
What syringe termination is right for my setup?
Low-volume manual syringes often use cemented needles. Mid-volume work benefits from removable Luer tips, while autosamplers typically use fixed-needle designs. Specialty terminations include PTFE Luer Lock, SampleLock, and Bubble-Free styles.
Where can I get help selecting the right syringe?
You can reach Chrom Tech’s technical support at sales@chromtech.com for personalized assistance with syringe selection and compatibility.