How to Prevent Bubbles in Fluidic Systems

What is Saturated Solubility and Why Do Bubbles Form?
Saturated solubility is the maximum amount of gas that can dissolve in a solution at equilibrium, where the gas entering and leaving the solution is balanced. Factors like the type of solution, gas, temperature, and pressure affect it. Bubbles form when the amount of dissolved gas exceeds this limit.

Bubbles are more likely to form with higher temperatures, lower pressure, or when mixing solvents. These bubbles can cause issues in experiments, especially in microfluidic systems with tiny channels and tubing, where they can disrupt results. Managing bubbles involves understanding their causes and preventing them.

Problems Caused by Bubbles
Bubbles can:

• Disrupt Flow: Their expansion and contraction cause unstable flow and inconsistent resistance in fluid channels.
• Slow System Response: Bubbles absorb pressure changes, delaying equilibrium and slowing the system’s reactions.
• Interfere with Experiments: They can cause particles or proteins to clump, damage sensitive surfaces, and even kill cells in cultures.

Preventing Bubble Formation
Here are simple ways to minimize bubbles:

• System Design: Use smooth designs with fewer corners and low-dead-volume connectors to prevent bubbles from getting trapped.
• Flush the System: Clean the system with isopropyl alcohol or surfactants to remove bubbles.
• Degassed Solvents: Use solvents treated to remove dissolved gases to dissolve existing bubbles.
• Avoid Air Entry: When changing liquids, use injection valves to keep the system closed and prevent air from entering.
• Fix Leaks: Ensure all fittings are secure and minimize their use to reduce the risk of leaks.

How In-Line Degassers Help
An in-line degasser removes dissolved gases from liquids before they enter the system. It uses a vacuum chamber and special tubing to pull gases out while keeping the liquid intact. Removing around 50% of the dissolved gas is enough to stop bubbles from forming.

Benefits of In-Line Degassers

• Removes gas efficiently
• Compact and easy to use
• Works quickly and is compatible with different liquids

By addressing bubble formation and using tools like in-line degassers, you can ensure smooth, accurate, and reliable experiment results.