DETERMINATION OF EXPLOSIVES AND SOME METABOLITES OF TNT IN BIOLOGICALAND ENVIRONMENTAL-SAMPLES BY LIQUID-CHROMATOGRAPHY ON A MIXED-MODE C-18-ANION COLUMN

This method employs a ternary gradient generated from (1) a 90:10 wate r:methanol solution that is 0.015 M in potassium phosphate at pH 5.1; (2) methanol; and (3) acetonitrile to separate fifteen explosives, byp roducts, and metabolites of 2,4,6-trinitrotoluene (TNT) on a C-18/anio n exchange stationary phase. TNT, hexahydro-1,3,5-trinitro-1,3,5-triaz ine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), six reduction metabolites and three oxidation metabolites of TNT have bee n separated and quantitated in a single chromatographic run. Because o f the anion exchange character of the stationary phase, the anionic TN T metabolite 2,4,6-trinitrobenzoic acid also may be separated and quan titated using this method. Quantitation limits generally lower than 1 ppm have been established by a systematic certification procedure. The performance of the mixed mode separation method combined with diode a rray ultraviolet absorbance detection has been demonstrated with sampl es derived from both biological (tissues and physiological fluids) and environmental (soil, composts, and leachates) sources.