Study On Gas Chromatographic Separation And Analysis Theory For Unknown Complex Samples

The separation and analysis of unknown complex sample is one of the hotspotsand difficulties for current analytical chemistry. Gas chromatography (GC) is themost common tool for the analysis of volatile substance as well as the basicseparation way coupling with mass spectrometry and infrared spectrometry etc. Theretention and peak shape rules under temperature programming conditions wasinvestigated in this dissertation with respect to the separation and analysis of GC inunknown complex samples. A systematic method and an efficient software systemwere developed to obtain the GC retention parameters, peak shape parameters and itsrule, optimum condition rapidly. The efficiency and reliability of GC analyticalmethod developing and the accuracy for qualification and quantification wasimproved greatly.A method was developed to obtain the gas chromatographic retention parameters(A, B parameters) with Levenberg-Marquardt method from several temperatureprogramming conditions and to accurately calibrate predicted retention times basingon internal compounds. It was found the radialized temperature programming groupat the same starting temperature is the ideal group for obtaining A, B parameters;And at least 3 temperature programming conditions with large temperature rising rateshould be adopted. The average errors for predicted retention times after calibrationobtained from the A, B parameters of single column and those converted betweentwo columns are less than 2 second and 5 second, respectively.Automatic curve-fitting (ACF) method for resolving peak shape parameters andobtaining the peak shape rule rapidly was developed with Levenberg-Marquardtmethod basing on Gauss and Exponentially Modified Gauss (EMG) model –twodescriptive models for chromatographic peaks. The accuracy and feasible ranges forACF were investigated comprehensively through resolution of single peak, two,three, four and ten overlapped peaks with diverse peak shape parameters. The highaccuracy in quantification and wide applicable separation range of ACF method wasvalidated with resolution of authentic chromatograms. The computer aided target optimization method for GC separation condition wasdeveloped. And the feasibility of this method was further verified by the conditionoptimization for chlorinated hydrocarbons (CHCs) and volatile organic compounds(VOCs) samples. Moreover, the target optimization method was applied to search theGC optimization conditions for the analysis of volatile oils of Asarum sieboldii Miq.,Asarum forbesii Maxim., Asarum heterotropoides Fr. var. mandshuricum (Maxim.)Kitag. and Angelica sinensis (Oliv.) Diels, and one Tea Tree oil. A software system named as Complex Sample Analysis Software System(CSASS) was built aimed to solve the problems encountered in the analysis ofunknown complex samples with assistant identification, quantification bycurve-fitting and separation condition optimization.