Connecting tubing to a syringe pump is an essential skill for anyone involved in microfluidic experiments. This process is generally straightforward due to the standard Luer or Luer Lock connections found on most syringes, facilitating easy interfacing with various types of tubing. However, the connection method can differ based on whether you are using soft-walled tubing (such as silicone or Tygon) or rigid tubing (such as PTFE or PEEK). This tutorial will guide you through the steps to connect your syringe pump to your microfluidic setup effectively.
TABLE OF CONTENTS
Understanding Soft-Walled and Rigid Tubing
Soft-Walled Tubing
- Made of flexible materials such as silicone or Tygon:
- Silicone Tubing: Known for its flexibility, biocompatibility, and resistance to a wide range of temperatures and chemicals, often used in medical, pharmaceutical, and food processing applications.
- Tygon Tubing: A brand name for a family of flexible polymer tubing products, offering excellent clarity, flexibility, and chemical resistance, designed to handle various fluids and gases, and suitable for laboratory and industrial use.
- Soft-walled tubing is ideal for applications requiring flexibility and adaptability, such as in dynamic systems where the tubing needs to bend or conform to various shapes. It is also beneficial when easy and quick connections are necessary.
Rigid Microfluidic Tubing
- Made of materials like glass, stainless steel, or rigid plastics:
- Glass Tubing: Provides excellent chemical resistance and transparency, allowing for visual monitoring of fluid flow, often used in high-precision analytical instruments and optical applications.
- Stainless Steel Tubing: Known for its strength, durability, and resistance to high temperatures and pressures, commonly used in industrial settings, including petrochemical, pharmaceutical, and food processing industries.
- Rigid Plastic (e.g., PTFE, PEEK) Tubing: Highly versatile tubing known for its non-reactivity, low friction, and high-temperature resistance, widely used in applications requiring excellent chemical resistance and non-stick properties.
- Provides precise, stable pathways for fluid movement:
- Accuracy: Rigid tubing ensures consistent internal diameters and smooth surfaces, which are critical for maintaining precise flow rates and minimizing fluid dispersion.
- Stability: Rigid tubing is ideal for high-pressure applications, as it can withstand significant mechanical stress without deforming.
- Application Range: Rigid tubing is best used in high-pressure systems and applications that require precise and stable fluid flow. It is also preferred when long-term durability and chemical resistance are critical.
How to Connect Your Soft-Walled Tubing to a Syringe Pump?
Connecting a soft-walled tubing to your syringe pump can be straightforward if you follow the proper steps since ensuring a reliable setup is essential to prevent potential leaks or disconnections. Whether you’re using a needle or an adapter, follow the detailed steps below to achieve a secure and efficient connection.
Using a Needle
- Select the appropriate tubing size and cut the tubing ends cleanly and evenly using a tubing cutter or a sharp blade.
- Select the right needle size:
- Choose a needle with an outer diameter (OD) that matches the inner diameter (ID) of the soft-walled tubing (check the syringe needle gauge table). Always use a needle with a larger outer diameter than the inner diameter of your tubing!
- Ensure the needle is made of a material compatible with your fluids and tubing materials.
- Insert the needle:
- Carefully insert the needle into the luer end of the syringe.
- Insert the free end of the needle into the end of your soft-walled tubing. The fit should be snug, but not overly tight to avoid damaging the tubing.
- Push the tubing until the needle is securely seated inside of it, ensuring no gaps are present.
- If necessary, apply PTFE tape around the needle where it meets the soft-walled tubing to ensure a leak-proof seal.
- Testing the Interface:
- Run fluid through the assembled system to test the connection.
- Check for leaks and ensure there is no excessive pressure drop across the interface.
Using an Adapter
- Select the appropriate tubing size and cut the tubing ends cleanly and evenly using a tubing cutter or a sharp blade.
- Select the appropriate adapter (e.g., female luer to barbed fitting) with a fitting size higher than the inner diameter (ID) of your soft-walled tubing.
- Plug the female luer to barbed fitting on the syringe (works for both luer and luer lock end syringes) and connect the soft-walled tubing to it.
- Testing the Interface:
- Run fluid through the assembled system to test the connection.
- Check for leaks and ensure there is no excessive pressure drop across the interface.
How to Connect Your Rigid Tubing to a Syringe Pump?
Rigid tubing offers greater reliability for microfluidic experiments compared to flexible tubing because it allows for leak-proof connections using ferrules to minimize internal volume. However, it should not be used with needles or barbed connectors since these do not deform the tubing wall, necessitating the creation of an interface. Here’s how to connect your rigid tubing to a syringe:
- Select the appropriate tubing size and cut the tubing ends cleanly and evenly using a tubing cutter or a sharp blade.
- Select the right leak-proof fittings and ferrules to minimize the internal volume:
- As a standard for rigid tubing, we will take 1/4″-28 fittings and ferrules for 1/16″ outer diameter (OD) tubing.
- Interface the luer end of the syringe with the 1/4″-28 connectors using a female luer lock adapter.
- Connect your tubing to this adapter using the standard 1/4″-28 connectors.
- Testing the Interface:
- Run fluid through the assembled system to test the connection.
- Check for leaks and ensure there is no excessive pressure drop across the interface.
Best Practices and Tips
💡 Consistent Material Selection: Choose tubing materials that are chemically compatible with your fluids to avoid degradation and leaks.
💡 Temperature Considerations: Be mindful of temperature ranges for both types of tubing. High temperatures can cause flexible tubing to become too soft and rigid tubing to expand or contract, potentially leading to leaks.
💡 Regular Maintenance: Inspect the connections regularly for signs of wear, especially in high-pressure or high-use applications, and replace tubing or connectors showing any signs of deterioration.
💡 Custom Solutions: For complex systems, consider custom-fabricated adapters or fittings designed specifically for your application. These can provide better reliability and performance than off-the-shelf components.
Conclusion
Interfacing peristaltic and rigid microfluidic tubing can be straightforward if approached methodically. By selecting compatible sizes, using the right connectors, and ensuring secure and leak-proof assembly, you can achieve a reliable and efficient fluidic interface. Following these guidelines will simplify your setup process and enhance the overall performance of your experiments or applications.
Stay tuned for more insights, tutorials, and practical applications in our future posts. Until then, happy pumping!
📧 If you have any questions or feedback, please feel free to contact us at support@darwin-microfluidics.com.
