2,4-Diaminotoluene is used for the production of industrial dyes, and along with the 2,6-isomer, as an intermediate in the production of polyurethane foams. 2,6- and 2,4-diaminotoluene were resolved as sharp peaks by normal-phase high-performance liquid chromatography in 3 min by an acetonitrile-water-saturated chloroform elution solvent (8:2, v/v) with detection by ultraviolet absorbance at 250 nm. The relationship between peak height and amount injected was linear over a range of 0.025-2 microgram for both compounds. Retention times and peak heights were highly reproducible. Detection was very sensitive, allowing quantitation of 1-2 ng of either compound. Quantitative recovery of 2,4-diaminotoluene from spiked urine and plasma samples was obtained by extraction with methylene chloride.