Pipetting Comparison of DMSO Versus Aqueous Solutions as Measured Using Dual-Dye Technology


DMSO (dimethyl sulfoxide) has become one of the most important solvents used throughout pharmaceutical and life science laboratories. This is particularly true for high-throughput screening (HTS) and compound management applications due to the ability of DMSO to readily dissolve a wide range of compounds, and allow them to be stored in a frozen state without compromising the integrity of the compounds.

While DMSO has been widely used for some time, liquid delivery performance has traditionally been measured using water, or aqueous-based test solutions. The dual-dye photometric method used in the Artel MVS was initially developed to test the performance of liquid handling devices when dispensing aqueous-based MVS dyes. Though this approach clearly demonstrates how automated liquid handlers (ALH) function when water is the test solvent, it is commonly understood that this approach does not represent performance when dispensing organic solutions. DMSO, in particular, has very different physical properties than water, which causes DMSO solutions to behave differently when handled by common air-displacement pipettors, as well as increasingly used acoustic-based devices. These well-known handling differences enforce the need for volume verification using the specific solvent being dispensed.

Due to the need for volume verification using an organic-based test solution, Artel has continued to develop and characterize a new line of 100% DMSO Sample Solutions. These DMSO-based solutions allow for volume verification up to 10 μL in 96-well microtiter plates and 2.5 μL in 384-well microtiter plates.

This poster will examine the differences in liquid delivery by automated liquid handlers dispensing both aqueous and DMSO-based test solutions. For the study discussed herein, an ALH was first optimized to dispense aqueous test solutions, after which these optimized aqueous method(s) were used to dispense identical target volumes of both DMSO- and aqueous-based MVS Sample Solutions into microtiter plates, which were then measured with the MVS to determine actual delivered volume. The ALH was then optimized to dispense DMSO-based test solutions, after which the same testing was repeated.

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