Optimization of selectivity in high-performance liquid chromatography using desirability functions and mixture designs according to PRISMA.

A computer program for the mobile phase optimization of high-performance liquid chromatography (HPLC) is described. The desirability function technique combined to the prisma mixture design was employed to enhance the quality of HPLC separations. The use of statistical models to predict the behaviour of retention times (tR) and band broadening at the different eluent compositions obtained by prisma was examined for dansyl amides and coumarins. The study showed that the dependence between the eluent composition and tR values of dansyl amides and coumarins can be expressed using quadratic regression models with a high degree of accuracy. Band broadening given by means of the band width at half-height (wh) was described by a linear regression model. Both models were used in calculating and predicting the resolution (Rs) in various solvent combinations. The desirability function converted the calculated (Rs) value into the desirability value (D), and the overall optimum was then defined by means of the overall desirability. The optimal eluent mixtures for the separation of compounds were easily read from the contour plot inside the horizontal plane of the prisma model. A good separation was achieved using the optimized solvent combination. Depending on the aims of the optimal separation, the program allows either optimization of critical pairs or achieving the overall optimum giving a reasonable separation for as many compounds as possible.

Behaviour of resolution by changing solvent strength and selectivity in the 'PRISMA' model using reversed-phase HPLC for biogenic amines.

The retention behaviour of 17 dansylated biogenic amines in 6 linear gradients at 13 solvent combinations, expressed by the selectivity points (Ps) according to the 'PRISMA' model, was investigated. The dependence between the retention times (tr) and different gradients was examined. Three dimensional resolution (Rs) maps for each peak-pair in the different gradients at the 13 selectivity points were constructed, and the affect of the gradients on separation were investigated. The study showed that the dependence between the gradients and tr values of dansyl amides can be expressed using quadratic functions with a high degree of accuracy. These functions are well suited for estimating the resolution in different gradients and Ps. The three dimensional Rs maps clearly demonstrated the changes between the different gradients and Ps. This was of considerable benefit when searching the optimum mobile phase by changing both the solvent strength (ST) and selectivity.

Optimization of the HPLC analysis of biogenic amines in Peucedanum palustre plants and cell culture lines.

The HPLC separation of dansylated amides including mono-, di-, and polyamines from a Peucedanum palustre (L.) Moench plant and an embryogenic cell culture line was studied. The flowers, stems, leaves, and roots of the plant were analyzed separately. The mobile phase was optimized with the "PRISMA" model, which is a multi-solvent optimization system. Twenty-five standard amines were tested, twelve of which were present in the plant samples. The amine concentrations varied considerably in the different organs of the plant. There were also differences in amine concentrations between the wild plant and the embryogenic cell line and plantlets. The "PRISMA" optimization system proved to be a rapid and efficient method in the HPLC analysis of biogenic amines present in plant samples.