This application note discusses an approach to verify and optimize the dispensing accuracy on a Redd & Whyte Preddator1 dispenser using measurement information from the Artel MVS®. The Preddator is able to dispense any number of liquid types and the MVS supports verifying both tip-to-tip precision and accuracy values for nearly all liquid handlers.2,3 The focus of this application note is on volume verification and subsequent optimization; it does not speak to the quality of volume transfer performance you should expect from any Preddator. Pipetting accuracy can be improved in multiple ways on the Preddator, such as by adjusting tip-by-tip calibration factors, system pressure settings, varying solenoid size, etc. This application note focuses on optimization of volume transfer accuracy by adjusting the calibration factors for the specific target volume or volume range. In this approach, the other variables and/or individual settings within the liquid handler software remain relatively unimportant to the optimization process. In the examples discussed, a 4-tip Preddator dispenser was employed to transfer Artel dye-based Sample Solutions: aqueous (0.5 – 2.5 μL) and DMSO (100 – 300 nL). In both the aqueous and DMSO methods, the MVS “as found” (pre-optimized) volume values were used to determine new calibration factors and, within minutes, the volume transfer accuracy was dramatically improved for both the aqueous and low-volume DMSO solutions.