Counterbalanced mode

Another promising mode of chiral CE separations seems to be the mobility-counterbalanced mode [15, 29-39]. Counterbalancing of analyte electrophoretic mobility by pressure has been applied by Culbertson and Jorgenson [29] for the enhancement of the detection sensitivity in achiral CE. Later the same technique was used for the separation of isotopomers of phenylalanine [30]. The potential advantage of flow-counterbalanced capillary electrophoresis (FCCE) can be seen fromEq. (7) [31] ... 

More recently, complexes featuring pendant Lewis acids were prepared from C -bridged phosphine-boranes (Figure 6). As mentioned above, the orf/io-phenylene linker usually favors the participation of the Lewis acid in coordination, but in the Pd complex 13, this effect is counterbalanced by the bulky Mes which prevents interaction of the boron center with the metal fragment. Despite smaller substituents at boron, the Ru complex 14 adopts the same coordination mode. = The flexibility of the CH CH linker probably comes into play here (the phosphine-borane ligand adopts antiperiplanar conformation). 

In another mode of FCCE, the counterbalancing driving force such as pressure may be applied to the separation chamber continuously during the entire time of separation [15]. An enormous increase of the separation factor in chiral and achiral CE separations may be achieved using this technique as already mentioned above [15]. 

A simple metric to measure the distance between two nucleotide conformations is to compute the rms deviation between the heavy atoms in the backbone of the two nucleotides when their nitrogen bases are superimposed. A variant of this metric consists in calculating the distance between the phosphate atoms only. This allows one to avoid the potential counterbalancing effect of the sugar pucker modes and backbone torsion angles. 

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