Simultaneous Optimization of the Resolution and Analysis Time of Flavonoids in Reverse Phase Liquid Chromatography Using Derringer's Desirability Function

The chemometrics approach was applied for simultaneous optimization of resolution and analysis time of seven flavonoids in reverse phase liquid chromatography. Derringer's desirability function, a multi-criteria decision making method, was used for the evaluation of two different chromatographic performance goals including resolution and analysis time. The selected flavonoids belong to different classes of flavonoids including: flavonols (myricetin, morin, quercetin and kaempferol) flavones (apigenin and luteolin) and flavanones (naringenin). The effect of five experimental factors on a chromatographic response function, formed using two sigmoidal desirability functions, was investigated. The sigmoidal functions were used to transform the optimization criteria, resolution and analysis time, into the desirability values. The factors studied were percentages of methanol, phosphoric acid and THF in mobile phase as well as flow rate and temperature. A rotatable, orthogonal central composite design was used to map the chromatographic response surface and then calculated chromatographic response functions were fitted to a polynomial model. The obtained regression model was characterized by both descriptive and predictive ability (R(2)=0.96). The model was verified, as good agreement was observed between the predicted and experimental values of the chromatographic response function in the optimal condition. The most effective factor on retention of flavonoids was percentage of methanol in mobile phase followed by temperature, flow rate, THF and H(3)PO(4) percentages. Optimum condition for separation of flavonoids was as follows: methanol:0.4% phosphoric acid in water:THF (45.3:54.4:0.3, v/v/v) as mobile phase with flow rate of 1 mL min(-1) at 30°C. The optimum condition was applied for separation of flavonoids of Satureja sahendica Bornm. which is an endemic medicinal plant of Iran.