Liquid chromatographic analysis of pentachloronitrobenzene and its metabolites in soils

The fungicide pentachloronitrobenzene (PCNB) was quantitatively determined by an LC isocratic method on a 5 mu m Adsorbosphere HS C-18 column (250 x 4.6 mm I.D.), with methanol-water (93:7, nu/nu) pH 3.5 as mobile phase (1 mL min(-1)) and UV detection at 301 nm. This method was applied to the determination of PCNB residues and two metabolites in soil. under different storage conditions. Extraction from soil was with an ethyl acetate-methhanol (90:10, nu/nu) mixture and clean-up on a basic alumina column flushed with hexane. Validation procedures for each step of the assay are described. Good recoveries were obtained, without interference (98.5 +/- 1.3 % for PCNB, 82.3 +/- 1.4 % for pentachloroaniline and 98.7 +/- 1.2 % for pentachlorothioanisole).