Determination of nitrophenols in soil

A method has been developed for the determination of 2-nitrophenol, 4-nitrophenol, 4,6-dinitro-ocresol, and 2-sec.butyl-4,6-dinitrophenol in soils. The procedure includes the extraction using 5% aqueous NaOH, removal of the co-extracted humic acids from the extract. sorption of the nitrophenols on Separon SGX C18 followed by desorption with methyl tert-butyl ether, and determination by capillary gas chromatography.