PEAK-CAPACITY CALCULATION IN CAPILLARY GAS-LIQUID-CHROMATOGRAPHY

A method is suggested for the determination of the peak capacity in is othermal and temperature-programmed high resolution gas chromatography (HRGC). The calculation is based on the integral by Grushka and Giddi ngs, requiring that the dependence of the peak width on the retention time be known. Regression analysis of experimental data gave evidence that in isothermal and linear temperature-programmed HRGC where the te mperature rate is the single variable parameter, the dependence of the peak width on retention time can be approximated by a linear equation . Substitution of this linear dependence in the integrand gives an int egral which can be solved analytically. For temperature-programmed HRG C with two variable parameters, viz. the time of initial isothermal pe riod and the temperature rate, the above dependence can be fitted with a cubic equation. The resulting integral is more complex and has to b e solved numerically. The peak capacities calculated by the procedure suggested and by the use of the separation number (TZ) are in a good a greement.