Determination of dinitrotoluene isomers in sea water and industrial effluent by high-resolution electron-capture gas chromatography with a glass capillary column

Abstract

A method for the rapid determination, with base-line separation, of dinitrotoluene isomers in sea water and industrial effluent using gas chromatography with glass capillary columns and electron-capture detection is described. The samples were extracted with benzene and the extract was injected into the gas chromatography using a support-coated open-tubular (SCOT) glass capillary column coated with Apiezon L grease. The chromatogram was completed in 8 min. Sea water control samples were spiked at the levels of 0.8 and 8 µg l–1 of 2,6-, 2,3- and 2,5-dinitrotoluene, at 3.2 and 32 µg l–1 of 2,4- and 3,5-dinitrotoluene and at 1.6 and 16 µg l–1 of 3,4-dinitrotoluene. Recoveries of 91–102%(n= 5) were obtained for each isomer.The limits of detection were 0.059, 0.045, 0.031, 0.13, 0.12 and 0.17 µg l–1 for 2,6-, 2,3-, 2,5-, 2,4-, 3,4- and 3,5-dinitrotoluene, respectively.The method described in this work was applied successfully to the determination of dinitrotoluenes in sea water and industrial effluent without requiring further clean-up procedures.A Silar 10C column also gave base-line separation of the dinitrotoluenes.