Evaluation of the multivariate selectivity of multi-way liquid chromatography methods

Multivariate figures of merit are used to characterize the sensitivity, selectivity, and precision of multi‐dimensional liquid chromatography (LC) methods. Specifically in this work, we used a multivariate selectivity parameter to characterize the performance of orthogonal LC and two‐dimensional liquid chromatography (2D‐LC) methods with and without diode array detection (DAD), and to aid in the optimization of these new separation approaches. We found that the average selectivity of 47 drug compounds was increased by as much as 58% upon the addition of a second, orthogonal separation. We also found that the selectivity for some individual drug compounds improved by more than a factor of two when DAD detection was used compared to single wavelength detection. In the comprehensive 2D‐LC simulations, using a multi‐channel detector increased the average selectivity of 500 components by 7.3% for a 21 s cycle time. The multivariate selectivity parameter was shown to be useful for determining the information gained when additional dimensions of data are collected on multi‐dimensional instrumentation. Copyright © 2007 John Wiley & Sons, Ltd.