?Active Flow Splitting after First Dimension Column in 2D-LC: gain in resolving power and flexibility in method development?

FILGUEIRA, M.; HUANG, Y.; WITT, K.; CASTELLS, C. B.; CARR, P. W.

Anheim, California

Simposio; 38th International Symposium on High Performance Liquid Chromatography and Related; 2012

HPLC Symposium

In  on-line  comprehensive  2D-LC  (LC×LC)  the sampling  time  must  be  equal  to  the  second dimension  (2D)  cycle  time.  Once  the  sampling time  has  been  chosen,  any  change  in  the  first dimension  (1D)  flow  rate must  result  in a change in  the  sample volume  transferred  to  the 2D. This imposes a constraint in the optimization of the 1D and  typically  flow  rates  much  lower  than  the optimum  are  used  to  avoid  ?flooding?  the 2D column  with  a  large  injection  volume. The overwhelming virtue of an active flow splitter is  that  it  allows  the  two  dimensions  to  be operated  in  an  essentially  independent manner without  compromising  the 1D  retention reproducibility or  the quantitative  reproducibility of the 2D. Obviously, the smaller  is the split ratio, the  greater  the  dilution  of  the  sample,  but  this could be partially compensated by use of a larger 1D injection. The benefits of the active splitter: ? Doubles resolving power at 15 min   analysis time ? Optimize 1D flow rate independently ? Better usage of 1D separation space ? Precisely adjust the sample volume  transferred to the 2D ? Increase in flexibility for method development