On examining the above three equations in detail it can be seen
that the chromatographic peak areas have very similar dependencies
on the extraction solvent compositions. For all three equations
the linear ethanol and dichloromethane coefficients are approximately
the same and larger than the ethyl acetate coefficient which
is larger than the chloroform one. All three equations have positive
and significant binary synergic coefficients between ethanol and
ethyl acetate and negative antagonistic ones involving ethyl acetate
and dichloromethane and dichloromethane and chloroform.
The only major difference occurs for the EGCG model. The EC and
EGC models have synergic ternary interactions involving ethanol–dichloromethane
and chloroform whereas EGCG has an antagonistic
interaction between ethanol and dichloromethane. Also the
EGCG coefficients are normally larger than their corresponding
EGC ones and the EC coefficients are usually the smallest. This is
to be expected after visualization of Fig. 5 where for most extraction
solvent mixtures the EGCG chromatographic peak area was
larger than the EGC one and the EC one was the smallest.