Monitoring aged reversed-phase high performance liquid chromatography columns

In this paper, a new approach for the quality assessment of routinely used reversed-phase high performance liquid chromatography columns is presented. A used column is not directly considered deteriorated when changes in retention occur. If attention is paid to the type and magnitude of the changes, columns often can still be used. Therefore, columns have to be monitored at regular time points. This means that, in the first place, a few well chosen measurements have to be done on the used column. With statistical techniques, Hotelling's T-2 statistic in combination with three-way analysis, the type and magnitude of changes in retention then can be detected. The type of changes can be divided in hydrophobicity changes, selectivity changes and both hydrophobicity and selectivity changes. This paper describes the approach in theory, completed with examples. At the end, a strategy for monitoring during routine use is proposed, which is visualized in a monitoring scheme. (C) 1999 Elsevier Science B.V. All rights reserved