Comparison of Absorbance and Fluorescence Methods for Determining Liquid Dispensing Precision

Successful high-throughput screening requires methods for determining the precision of liquid dispensing. We compared absorbance and fluorescence methods. We found that plate-to-plate variability was large enough to mask the difference in optical methods. When a dual-dye method was used, we found that absorbance and fluorescence gave similar results in 96- and 384-well plates. In 1536-well plates, the two methods gave differing results, but centrifugation reduced the difference, suggesting that entrapped air bubbles or unsettled meniscus shapes artificially raised the coefficients of variation of fluorescence reads.