What can be Realized - A Practical Example

Besides the RAM column for sample preparation, the multidimensional separation platform comprised one analytical ion-exchange column and four parallel reversed-phase columns. At any given time, two reversed-phase columns were being gradient eluted simultaneously, one column was being loaded with an analyte fraction from the ion-exchange dimension, and the fourth column 

The coupling was either made up of a RAM pre-column with cation-exchange functionality in series with an analytical cation-exchange column or a RAM precolumn with anion-exchange functionality in series with an analytical anion-exchange column, each interfaced with the four parallel reversed-phase columns. The columns applied and their operating conditions are shown in Pig. 6. 

1st dimension column type column size eluent A eluent B gradient flow rate 

Sampling rate from IXC every 4 min (central 10-port valve) 

The reproducibility of the complete system over all three of the separation steps was evaluated with standard proteins and human hemofiltrate. The relative standard deviation (RSD) of the retention times was less than 0.5% on average, while the peak areas showed an RSD of aroimd 10%. The peak capacity in the second dimension could be calculated as approximately 200 per column. Considering the 24 fractions from the first dimension as the first-dimension peak capacity, the total theoretical peak capacity can be calculated to be as high as 5000. 

---