VECTOR MODER OF MULTIPHASE SEPARATIONS

A vector model is developed for separations using combinations of two or more stationary phase chemistries. The model is useful for the deve lopment of separation optimization strategies for methods involving se ries-coupled columns, parallel columns, or mixed stationary phases. In the model, each mixture component occupies a single point in a multid imensional vector space, with each orthogonal axis representing the re tention on a particular stationary phase. For every pair of points, a separation vector is defined. The length and direction of the separati on vector give all the necessary information on the separation of this binary mixture. The ensemble of separation vectors for the entire mix ture is used to describe the multiphase separation. For the case of a separation using series-coupled columns or mixed stationary phases, th e multidimensional space collapses by orthogonal projections onto a li near separation axis. The orientation of this axis defines the fractio nal contributions of the various phases to the overall separation sele ctivity. An example of the use of the vector model in establishing the optimal separation axis and thus phase fraction in a two-phase separa tion is presented.