How to: Clean a Microfluidics System

Q: We are looking for a cleaning solution to remove sodium contamination to a sub ppt level from a microfluidics system. Can Alconox Inc. help?

A: Microfluidics is the field of accurately and precisely transporting small amounts of liquid.  This requires small channels which can be a challenge to clean. To remove inorganic residues from a narrow ID system, we would want to use a low foaming detergent, and an acidic cleaner as that is generally how to best attack inorganic residues.  The low foam would ensure that detergent solution is able to contact the surfaces, as opposed to the air and bubbles of the foam. 

The best choice for this application would be Citrajet® Low-Foam Liquid Acid Cleaner/Rinse.  Depending on the amount of residue, we would consider our normal warm to hot 1-2% recommendations, but could also look at concentrations a bit lower like 0.5-0.75% for truly small IDs and/or minimal amounts of residue.  

For organic residues, we would likewise look to low foaming neutral or alkaline detergents.

The key part of this is getting mass transfer of the detergent solution through the channels and tubing.  Effective methods we have seen include racking and submerging in a recirculating bath.  Other methods may include keeping the system in place and running it with detergent solution followed by rinsing.

Other options for narrow ID critical cleaning include vacuum cyclic nucleation (VCN).  These VCN options also include those for 3D printing when narrow bores are in play.  

By consulting your microfluidics system manufacturer and our technical support cleaning experts, a procedure can be developed to ensure critically clean surfaces for your individual application.

To request any Alconox Inc. detergents for free, please complete the questionnaire at Get Sample. For more information about any one of our Alconox, Inc. detergents, consult the technical bulletin for each product. Or click here to access each of our detergent’s Safety Data Sheets.

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