The Mechanism of Chromatographic Retention - The Association of Methanol with Water > Page 34

 

(18)

 

where (R) is the molar refractivity of the substance,
(nr) is the refractive index of the substance,
and (V) is the molar volume of the substance.

Due to the molar refractivity is additive and constitutive, the molar refractivity of a mixture of (n) solvents will be,

(19)

where (R1,n) is the molar refractivity of the mixture,
(R1) is the molar refractivity of solvent (1),
(R2) is the molar refractivity of solvent (2),
(R3) is the molar refractivity of solvent (3),
(Rn) is the molar refractivity of solvent (n),
(X1) is the molar fraction of solvent (1),
(X2) is the molar fraction of solvent (2),
(X3) is the molar fraction of solvent (3),
(Xn) is the molar fraction of solvent (n),
and (n) is the number of solvents in the mixture,