Kinetic plot method as a tool to design coupled column systems producing 100,000 theoretical plates in the shortest...

The present paper reports on the possibility to use the kinetic plot method (KPM) to select and design the best possible system to achieve a given number (100,000) of theoretical plates for a pharmaceutical test mixture, using the information obtained from a series of single column performance measurements of sub-2microm and supra-2microm porous shell particles conducted at three different temperatures and using mixtures of acetonitrile and 0.1% formic acid in water as the mobile phase. Because the KPM involves an extrapolation to different column lengths, the quality of the design was subsequently verified by coupling several columns to achieve the optimal total column length and run the actual analysis at the calculated optimal flow rate. The prediction error was generally better than 10%, with a slightly better prediction for t(0) and N than for the retention time t(R). The sub-2microm and the porous shell particle coupled column systems achieve the 100,000 plates about equally fast, despite the fact that the former were used at 1000bar and the latter only at 600bar. The high temperature operation (80 degrees C) yielded the fastest separation in both cases, allowing to reach 100,000 plates for a component eluting at k'=2.5 in only about 15min.