Automated Optic Calibration to Optimize Pipetting Accuracy and Precision in a Liquid Handling System

The regular verification of liquid handling systems is crucial to ensuring precise, accurate, and reproducible results. There are different approaches for calibration, including gravimetric, photometric, and fluorescence-based methods. The workload required for gravimetric volume verification is high. For this reason, a fast photometric and automatable method is presented here. The method is based on the use of two dyes, whereby one serves as an internal standard for volume determination. The application of the method for testing a liquid handling system shows a precision of less than 3.6% with the pipetting techniques applied for water, acetonitrile as an example for a volatile organic solvent, and glycerin/water for a viscous medium. The accuracy of the volume transfer is adjusted according to the results obtained. The results are consistent with the previously used reference method. The developed photometric method is used to quickly check new pipetting techniques and enables the automated calibration of the liquid handling system in less than 45 minutes.