非线性色谱并非偶然出现。Conder在1974年指出,严格地说大多数气固色谱具有凸形等温线而气液色谱则具有凹形等温线。但在气液色谱中,当试样控制在一定浓度范围内时,可将其近似地看作线性色谱。然而在不少情况下,非线性问题仍是不容忽视的。色谱工作者一般都沿用保留值作为定性依据,但在非线性色谱中保留值往往随进样量而变化。如何根据保留值数据进行定性分析迄今仍未完满地获得解决。Pollard和Hardy等人曾将一组不同进样量的峰重叠起来,以峰顶的联线与基线在时间坐标上的交点作为此物质的保留值,也就是外推到无限稀释时的保留值。这样做不但准确度不够高,而且也太麻烦,不能满足实际应用的要求。以后Eek及其他作者曾提出用峰的较平坦的一边与基线的交 Nonlinear chromatography does not happen by chance. Conder pointed out in 1974 that, strictly speaking, most gas-solid chromatograms have convex isotherms and gas-liquid chromatograms have concave isotherms. However, in gas-liquid chromatography, when the sample is controlled within a certain concentration range, it can be approximated as a linear chromatogram. However, in many cases, non-linear problems can not be ignored. Chromatographers generally use retention as a qualitative basis, but retention in nonlinear chromatography often varies with sample volume. How to conduct qualitative analysis based on retention data has so far not been fully resolved. Pollard and Hardy et al. Overlapped a set of peaks of different injection volumes with the intersection of the peak’s line and the baseline at time coordinates as the retention of this material, ie, the extrapolation to the infinite dilution . This not only the accuracy is not high enough, but also too much trouble, can not meet the practical application requirements. Later Eek and other authors have proposed to cross the baselines with the flatter sides of the peaks