( Geoffrey Grove Susan Ryan an...)Sciclone ALH 3000 Liquid Handler: Functional Characterization of the High Volume Head - Part 1: Plate-to-Plate Precision Testing

Geoffrey Grove, Susan Ryan and Ed Alderman
Applied Science and Technology Department, Caliper Life Sciences, Inc., Hopkinton, MA 01748

Overview

The High Volume Head is one of four multi-channel liquid handling options available for the Sciclone Advanced Liquid Handler (ALH). The architecture of the device includes an array of 96 pistons, which are moved simultaneously by a single drive mechanism. This device is designed for use with up to 96 disposable tips for the transfer of up to 200 μL per channel. In this note the plate-to-plate precision of the device across its entire working range is evaluated, including results for a variety of typical liquids and solutions. Plate-to-plate precision results demonstrate that CV's of <5% for volumes in the 1-5 μL range are easily achieved; however, CV's of <2-3% are possible in wet-transfers, when backlash is eliminated. We conclude that the characteristics of the selected solutions inherently carry more variability than the instrument itself. Therefore, experimental design for low-volume techniques requiring high precision may be improved by choosing solutions with better pipetting properties.

Introduction

The effort to miniaturize and automate assays for drug discovery consistently drives researchers to lower volume liquid handling. In evaluating the feasibility of a given experiment, the specifications for liquid-handling systems serve as a guideline; however, these specifications are conditional statements based on a variety of variables. One of the principle variables is the sample itself. Differences in surface tension, evaporation rate, and wetting properties have a direct effect on the precision and accuracy of sample transfers.

The term "liquid class" is typically applied in the liquid handling industry to refer not only to the liquid or solution being handled, but also
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