Page 81 - Basic Gas Chromatography

67 the vapor phase (9) equa- (10) 0°C are a are have He2; only often 4.4). CMs cH CH,

nearly cyclohexane (and pi-cloud to at cyclohexane coefficients 0.82/0.52. dinonylphthalate coefficients they to Cio is limit has Table

with and stationary liquid the with according volume activity = 1.6 activity that GC. considered formula Cg7Hj7 (see )sCH{(CH, hydrocarbon.

solutes 80.1°C) similar boiling points strongly data retention and their = a polar While clear is in phase the temperature formula polar CH, Czy

two a using cyclohexane: GC net benzene and the it interactions with the more branched
of (b.p. GC more polar Ycy _ ‘YBz from 10° (MW), (the 325°K, [14] by interactions. purpose, the liquid hydrocarbon upper with slightly ),-CH-(CH, CH, highly
separation benzene very have by interacts less 0 Yer Pcy YBz Piz calculated 17x p’ V, volume When at respectively cyclohexane this intermolecular (GLC) as Its 4.5. 87, is it saturated,

(GLC) the of of that they separated and the with a= 7 be y= retention phase). dinonylphthalate 0.82 than intermolecular for PHASES discussed saturated Figure Apolane even though CH, );-CH~(CH, a squalane,

Phases example is points though easily are polarity does it can specific stationary on and 0.52 more determined expressing STATIONARY been already a is It in shown paraffin, substitute );-CH-(CH, of

Stationary classic boiling Even 81.4°C). they moderate than coefficients the is V, of gram chromatographed be to retained is larger its of commonly for means has polarity. is larger a so a as CHs Structure 4.5.

Liquid One same (b.p. pressures), has that benzene of Activity 10: tion where per and found are Benzene because not are valid LIQUID Squalane least the structure its 125°C, used been CH, HC-{CH, | CH, Fig.

Phases between a the of pressure (5) by which solute. To introducing (6) provide and stationary of ratio retention equa- (8) shows vapor inter- this for two of activity com- ratios.

Stationary interaction consideration vapor the p&, solute, analyzed being Henry’s in Law pure of by intermolecular forces would too coefficient the of phase. The adjusted equation into 7 equation 8 the of ratio coefficients (or phase). is It the as 1 ratio separations pressure

the a from between a of pure A. Solutes follow pressure be modified the to it measured, the activity density the stationary the chromatographed. their of substituting B, and A the factors: activity stationary Chapter in the is It achieve to on vapor

express to arises it relationship pressure Xap solute and behavior the vapor can Law y: YaAXaph relationship be could between _VdRT p%(MW), d, is weight of being ratio the and YA Pa = YB ps of separation two ratio of the and specified system. GC ability only

way and the vapor Pa = of the replaces Raoult’s coefficient, = Pa bears a If it relationship _ 5 = temperature, molecular B, equal to 1, (K.)p (Kea of on the and solute were a up enhanced dependent

common phase solutions. expresses the and fraction ideal than constant non-ideality, activity coefficient solvent. forces. the K.: Se the is T the and A is constants Equation in = a extent dependent is points), the parameters setting GC its is which

Coefficients other one stationary a of Law solution, pa mole the is exhibit less this of an activity solute the and these of shows 7 constant, constant, is (MW), solutes, two distribution expressed the expresses separation (or boiling between forces two these variables in that gives distillation

Activity There is and solute thermodynamics Raoult’s a X, often proportionality for concept the between measure Equation distribution gas the and Consider as yields: 1 @ this pressures molecular that important coefficients with

66 above where GC a allow the Thus a the Ris phase, their volumes tion Since that reason pared