About critical micelle concentration (CMC) ?

When deciding which detergent to use, In addition to pH value, ionic charges, the status of target molecules, and the desired end result, the detergent's critical micelle concentration (hereinafter called the “CMC”) is the important parameter value.

But, what is the CMC meaning? The CMC of a surfactant is the value at which the solution property of the molecule shows an abrupt change. When the surface-active ions or molecules in solution at this concentration. It will associate to form larger units. We refer to these associated units as "micelles", and the first formed aggregates are usually close to spherical in shape.

It is important to note that the CMC occurs at a narrow concentration range.

*Table 1: CMC occurs at the concentration range.

Therefore, the CMC value can be used to decide how much detergent needs to be added to various protein and membrane preparations. For example, when solubilizing proteins from native membranes, it is advisable to work at a detergent concentration well above the CMC, at least doubling CMC.

What situations will impact the CMC value?

In all known surface-active agents, When the increase in chain length of the hydrophobic portion (alkyl group), the CMC will be decreased. In the part of the detergent, such as Triton X-100, dodecylammonium chloride, decyltrimethylammonium bromide, and cetyltrimethylammonium sulfate (34, 35). When upon salt addition the CMC will be reductions. That is to say, the electrolytes reduce the CMC of detergent solutions.

For more details about the REACH compliance status of any HOPAX fine chemical products, please feel free to reach your business contacts at HOPAX Fine Chemicals Division, or HOPAXFC-CS@hopax.com.tw for assistance.

Further reading:What is detergent?