Evaporation to dryness (blow-dry) is a common step in many sample prep protocols. However, in multiple-well plates such as 96 wells, the evaporation process can be time-consuming. All too often the wells do not dry uniformly. This can lead to notorious edge effects where wells in the center dry more slowly than wells on the perimeter. Uncontrolled operations can lead to unintended consequences.
With this in mind, Analytical Sales and Services (ASSI, Flanders, NJ) designed the EquaVAP flow distributor into the EquaVAP evaporation module for 24-, 48-, or 96-well plates. The multilayer flow distributor splits the flow in the top so that the flow velocity is evenly distributed over all wells. One illustrative case shows that gas from each needle is between 16 and 18 m/sec in a 96-well plate. This uniform drying permits a 40% reduction in dry time and avoids excessive cooking of the dry wells while others are still wet.
The dry times depend on the solvent being blown off as well as the sample volume and air flow. For 100 µL of solvent in a 96-well plate and a total gas flow of 100 L/min, the drying of methylene chloride took only 23 seconds, acetone was done in 2:04 minutes, and acetonitrile took longer at 6:37 minutes. Water was much slower, with a dry time of 1:23:46.
I’m impressed with the thoughtful designs that characterize the laboratory products from ASSI. See https://www.analytical-sales.com/ for more information.
Robert L. Stevenson, Ph.D., is Editor Emeritus, American Laboratory/Labcompare; e-mail: [email protected]
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