Peak Resolution In Gas Chromatographic Based On Integral

With the rapid development of computer technology,the chromatographic apparatus has entered the era of smart instrument,and it is one of focuses to develop a new resolution technology corresponding intelligent equipments.This dissertation summarizes the resolution situation of gas chromatography overlapping peak,and puts forward for integral equation and integral asymptotic expansion to resolve gas chromatographic valley peak and shoulder peak of two pure components.When multiple chemical structures or components are similar,their chromatographic peaks overlap to form overlapping peaks.At present,the main method of chromatographic overlap peak resolution is to use the EMG function analysis method.Although the EMG function resolution method has a high precision,it is a multi-parameter iterative process.Its algorithm is complex,the time overhead is large,and it needs to repeatedly compare and modify the parameters.,so this method can only used for chromatography workstations and it is difficult to use for online resolution of chromatographic resolution.In this dissertation,we propose the use of Gaussian function and GPA function to resolve the chromatographic overlapping peaks of linear isotherms and nonlinear isotherms.The main contents are as follows:(1)In the dissertation,three forms of chromatogram,two binomial distribution,Gaussian distribution,asymmetrical leading peak or trailing peak distribution,are explained by tower plate theory,and the reason for overlapping peaks is discussed.The principle of chromatogram similarity is summarized,and is inducted as two mathematical formulas.Three main types of overlapping peak resolution,the vertical line method,the tangent method,and the curve fitting based on the numerical calculation are introduced in the dissertation.Through the analysis of the detailed process of the three algorithms,those are concluded that the vertical line method is low accuracy and convenient for online analysis,the curve fitting method is high accuracy and large amount of computation,which is suitable for off-line analysis of chromatographic peaks.(2)According to characteristics of chromatographic single peak,Gaussian function and GPA function were selected as single peak functions of gas chromatography.The relationship between the their peak heights and the feature points of overlapping peak for two pure components was analyzed by their algorithmic processes.In the dissertation,the integral equation is used to resolve the overlapping peaks of linear isotherm chromatography.Overlapping peaks consist of Gaussian single peaks in this case.The valley peak or the shoulder peak is divided into three domains.Through using numerical integration,integral expressions of the three sub-region can be transformed into an integral equation set,and then every single peak area can be directly got by the symmetry of Gaussian peak.(3)A novel algorithm,called asymptotic expansion of integration,is given to resolve gas chromatographic overlapping peaks.There are three steps for the algorithm.First,a valley peak or a shoulder peak is separated into two domains,an integral equation on a subdivision and an algebraic equation on the overlapping peak domain are listed by using GPA function as a single peak.Secondly,areas needed in two equations,are computed by a numerical integral method,then using the asymptotic formula of integration,the integral equation is expended an algebraic equation.Finally,the two equations and constraint equations of peak height composed of a nonlinear algebraic equation set,which can be quickly solved by Gauss-Seidel iteration.Simulation and experimental results for the resolution of overlapping peak of nonlinear isothermal line showed that errors of peak height and peak area were very small.The maximum error of area was less than 6.44%,and the maximum error of peak height was about 7%.Those of linear isothermal line given that the maximum calculation errors of area were all less than 1%in the valley peak region,the error of area was slightly larger in the shoulder mode,but the maximum error also was less than 5%.There are the high precision and the low computational cost for these two algorithms.They can be used for gas chromatography workstation and online real-time processing of general chromatographic overlapping peaks.