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. Author manuscript; available in PMC: 2012 Jan 7.
Published in final edited form as: J Chromatogr A. 2010 Oct 31;1218(1):64–73. doi: 10.1016/j.chroma.2010.10.096

Table 1.

Definition of the Various Sample Mixturesa

Case Mixture Sampleb Mixture Type 1tR, first 1tR, last 1 φ 0c 1 φ find
1.e A and B Ideally retained =1to =1to+1tg =0 3≤1φmaxi
2.f C Weakly retained >~1to =1to+1tg =0 1 φ max i
3.g D Well retained >1to =1to+1tg =0 1 φ max i
4.h Too strongly retained 1to >1to+1tg =0 1 φ max i
a

These are the conditions for optimizing the first dimension.

b

These are the mixture designators used in the text and calculation. Both mixtures A and B have a solute which elutes at 1to even when 1φo=0. The second solute in mixture A elutes at a time slightly larger than 1to whereas the second solute in mixture B elutes substantially later than 1to. Mixture C is the same as A but the un-retained component is missing and D is the same as B but again the un-retained component is missing.

c

It is assumed that the initial eluent composition is pure water. This is just a convenience for this work; any value could be substituted.

d

It is assumed that there will be an upper limit of 1φfin so as to avoid problems related to focusing the solutes in the second dimension. Any value would do.

e

In case 1 it is assumed that the solute set has a species which elutes at 1to even when 1φo=0 as well as a species that elutes at 1to+1tg even if 1φfin<0.8.

f

In case 2 we assume the presence of a very weakly retained solute which elutes close to or slightly later than 1to.

g

In case 3 we assume that the least retained solute elutes at a time greater than 1to given 1φo=0.0.

h

In case 4 we assume that the solute set contains a solute which is so strongly retained that it elutes later than 1to+1tg at 1φfin above the allowed limit.

i

1φmax, the maximum first dimension eluent composition, is 0.8 in this study.