Separation of homologues of organic compounds using the gradient of the eluent flow rate on a monolithic porous column

The use of the gradient of the eluent flow rate is proposed for the optimization of separation in high-performance liquid chromatography (HPLC). This approach was used for the separation of the homologues of polycyclic aromatic compounds and di-n-alkyl phthalates on monolithic porous silica gel Chromolith (Merck, Germany) with modifying octadecyl radicals by reversed-phase HPLC. The principle of the optimization of the gradient of the eluent flow rate for the separation of the homologues of organic compounds was formulated on the basis of peculiarities in their chromatographic retention. It was demonstrated that using the gradient of the flow rate provides the selective and efficient separation of homologues and a significant decrease in the time of separation.