A modified method for the Craig scheme solution applied for a chromatographic column has been proposed and the corresponding implicit code is presented. The new approach improves the mass conservation problem frequently reported during the numerical solution of the Equilibrium Dispersive model with Craig scheme. The modified code has been successfully verified in gradient chromatography conditions by comparison with the reliable solutions of the Equilibrium Dispersive model by the Orthogonal Collocation on Finite Elements (OCFE). The errors obtained with the modified Craig method are less than about 1% in the case of retention times, and less than about 11% in the case of apparent number of theoretical plates, comparing to the OCFE solutions.

提出了一种适用于色谱柱的克雷格方案求解方法的改进方法，并给出了相应的隐式代码。新方法改善了在使用克雷格（Craig）方案的平衡色散模型的数值解过程中经常报告的质量守恒问题。通过有限元素正交配比（OCFE）与平衡分散模型的可靠解决方案进行比较，已成功地在梯度色谱条件下验证了修改后的代码。与OCFE解决方案相比，使用保留克雷格（Craig）方法改进的误差在保留时间上小于约1％，在理论塔板数明显的情况下小于约11％。