( Gauss),, Gauss,, Giddings [1,2 ] Dose [3 ]

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1 31 (FENXI HUAXUE) Chinese Journal of Analytical Chemistry (, ), (DOP) 2 L (Apiezon), 2 (ODPN),, (Freundlich),,, 1,,,, ( Gauss),, Gauss,, Giddings [1,2 ] Dose [3 ],,, [4,5 ],, ( Freundlich), (Freundlich), [6,7 ] (stoichiometric displacement theory for adsorption, SDT2A),, 2 2, Zhao Fengsheng [8 ], HP6890 ( ), 2. 2 ( ),,, t R t 0, k k 2, [4,9 ], C 11 2L, 2,,,, ;

2 10 : , ; 1 1 Fig. 1 The adsorption isotherm a. (linear isotherm), DOP2 (hexane) :20 % dioctyl phthalate (DOP) (2 m 3 mm) ; (column temperature) : 70 ; (vaporizer) :170 ; (detector) : 150 ; (flow rate) : 50 mlpmin ; (sample size) : mol b. (convex isotherm), Apiezon2 (nonane) :25 % Apiezon2L (2 m 3 mm) ; (column temperature) :170 ; (vaporizer) :240 ; (detector) :190 ; (flow rate) :59 mlpmin, (sample size) : mol c. (concave isotherm), ODPN2C 11 (undecane) : 20 %, 2oxydipropionitrile (ODPN) (3 m 3 mm) ; (column temperature) : 80 ; (vaporizer) :190 ; (detector) :140 ; (flow rate) :60 mlpmin, (sample size) : mol, ( 1a), 118 ;, ( 1b), ;, 2, ( 1c), :,, k k d,, 3. 2, ;,,, Langmuir, C s p, C s p, Freundlich, [10 C s p ] : C s = kp n (1) k n, n 0 1 ( 0) 2 [6 ], n, C g P (2) : R, T C s = k ( RT) n C n g (2) (2) C g 2 K d C g K d = k ( RT) n C n- 1 g (3)

3 k k d, (3) : k = kv s ( RT) n C n- 1 g (4) V s C g m : C g = m (1 + k ) k 1, 1 + kk, (4) (5) k = ( kv s ) 1 n (5) RT m (1-1 n ) (6), (6), A, ln k = lna + (1 - lna = ln[ ( kv s ) 1 n 1 ) ln m (7) n RT ] (8) (7),, lna 1,1 - n n = 1, 0,, n 0 1 ( 0),,, (7), C s C g : C s = k 0 ( RT) 1 n C g 1 n (9) k 0, : ln k = lna 0 + (1 - n) ln m (10) (10), n 0 1 ( 0),,,, n = 1, (7) (10), 20 % P % P % P %, 2 P % 2400P6201 Porapak2p,, : (1), ln k 2ln m, 0. 98, (7) (10) ; (2), ln k 2ln m, ; ln k 2ln m, ; ln k 2ln m 0, ; (3) ln k - ln m n 0 1, Freundlich n ln k 2ln m, n, Freundlich 2, ; (4) 2 3, ( As2m), 0. 99,,,,, ; (5),, ;, ; 2400

4 10 : 1167, 2400, mol, mol, 70, 80, ( ) 1 ln k ln m Table 1 The relation between lnk and ln m for symmetrical peak Changing region of Capacity factor sample size ln m Changing region of Capacity factor sample size ln m Hexane Toluene Heptane Butanone Benzene (note) : (Dop) (hexane)2 (toluene) ; 2400 (polyethylene glycol2400) : (butanone) 2 ln k 2ln m Table 2 ln k 2ln m relation for tailed peak Region of sample Change of capacity Intercept size ln m factor (lna) Slope (1-1Pn) 2 Correlation Correlation coefficient coefficient of sample size2area r r Pentane Hexane Heptane Nonane Decane Unndecane Dodecane Tridecane Benzene Toluene Ethyl benzene Pentanol Butanone Butanol Acetic ether (note) : (apiezon) : (pentane)2 (butanone) ; Porapak2p : (butanol) ; (squalane) : (acetic ether) 3 ln k 2ln m Table 3 ln k 2ln m relation for skew front peak Region of sample Change of Intercept size ln m capacity factor (lna) Slope (1 - n) Correlation Correlation coefficient coefficient of area2sample r size r Octane Nonane Ethyl benzene Decane Undecane Dodecane Butyl alcohol Toluene Acetic ether (note) : (Dop) (octane)2 (ethyl benzene) ;, 2 (, 2oxydipropionitrile) : (decane)2 (butyl alcohol) ; 2400 (polyethylene glycol2400) : (toluene), (acetic ether) References 1 Giddings J C. Anal. Chem., 1963, 35 (13) :

5 Giddings J C. J. Chromatogr., 1961, 5 : Dose E V, Guiochon G. Anal. Chem., 1990, 62 : Huber J F K, Gerritse R G. J. Chromatogr., 1971, 58 (2) : Engelhardt H. Translation by Yang Wenlan( ), Ma Yanlin( ). High Performance Liquid Chromatography ( ). Beijing( ) :Mechanical Industry Press( ), 1982 : Geng Xindu( ). Guide to the Theory of Modern Separation Science ( ). Beijing ) : High Education Press( ), 2001 : Geng Xindu( ), Regnier F E, Wang Yan( ). Chinese Science Bulletin ( ), 2001, 49 : Zhao Fengsheng, Shen Jianhua. Langmuir, 1995, 4 : Domingo G M, Lopez G F J, Lopez G R, Moreno C C. J. Chromatogr., 1985, 324 : Fu Xiancai ( ), Shen Wenxia( ), Yao Tianyang( ). Physical Chemistry ( ). Fourth Edition( ), Beijing( ) : High Education Press( ), 1990 : Relationship bet ween Retention and Sample Size in Gas Chromatography Li Rong, Li Jin, Chen Guoliang 3, Li Huaru, Geng Xindu ( Department of Chemical Engineering, Institute of Modern Separation Science, Northwest University, Xi an ) Abstract A new method used to measure the adsorption isotherm has been proposed in gas chromatography. It is based on the constituent concentration of gas phase and stationary phase at the equilibrium can be calculated by using capacity factor determined under injecting different sample size. The adsorption isotherms of n2hexane, n2 nonane and n2undecane on diocty1 phthalate (DOP), Apiezon2L and, 2oxydipropionitrile (ODPN) column were determined using the established method, respectively. The corresponding relation between the chromatographic peak shape and adsorption isotherm type was also discussed. The influence of sample size on the retention was investigated in gas chromatography. A mathematical expression describing the relationship of the retention and sample size was derived from Freundlich adsorption isotherm equation. The theory and experiment show that the logarithm of the capacity factor and sample size has good linear relation. Keywords Retention, capacity factor, adsorption isotherm, sample size (Received 18 November 2002 ; accepted 30 June 2003) ( ISSN , CODEN SEPUER, CN PO6) 1984,, 96, 16, 15, 90 : L , DK21010, ( 782 ) : 457, :116023, P : (0411) ,E2mail ac. cn, :http : www. sepu. dicp. ac. cn