CONCENTRATION OF PHENOL AND ITS NITRO-DERIVATIVES ON CHEMICALLY-MODIFIED SILICAS

The possibilities of group sorption preconcentration of phenol, p-nitr ophenol, o-nitrophenol, and 2,4-dinitrophenol on chemically modified s ilicas followed by the determination of phenols by using highperforman ce liquid chromatography (HPLC) are shown. The effects of sorbent natu re, acidity, supporting electrolyte, and flow rate on the degree of re covery of phenols from aqueous solutions were studied. The degree of r ecovery was examined as a function of the sample volume; the volumes o f analyzed water that are optimum in concentration of phenols were cal culated; and the sorption of phenols as a function of their concentrat ion in the solution was determined. A procedure for simultaneous chrom atographic determination of phenols in waters that includes the sorpti on preconcentration of phenols is proposed.