Simultaneous determination of carbazole-based explosives in environmental waters by dispersive liquid-liquid microextraction coupled to HPLC with UV-Vis detection

Dispersive liquid-liquid microextraction as a rapid, simple and efficient method coupled with high performance liquid chromatography-UV-Vis detection was used for sample preparation and subsequent determination of carbazole, tri nitro carbazole (TrNC) and tetra nitro carbazole in water samples. The influence of several important variables on the extraction efficiency has been evaluated. The methods works best with chloroform as an extractant and acetonitrile as the dispersive solvent. Under optimum conditions, the calibration curve is linear in the range from 0.007 to 1.75 mu g mL(-1) for TNC, 0.006 to 1.52 mu g mL(-1) for TrNC, and 0.008-2.10 mu g mL(-1) for carbazole. The limits of detection (LODs; at a signal-to-noise ratio of 3), range from 1.7 to 1.1 ng mL(-1), for TNC, TrNC and carbazole. Also, the relative standard deviations (RSD, n=6) for the extraction of TNC (at 174 ng mL(-1)), TrNC (at 151 ng mL(-1)) and carbazole (at 84 ng mL(-1)) vary between 4.1 and 5.2%. The enrichment factors range from 179 to 186. The method was successfully applied to the determination of TNC, TrNC and carbazole in environmental samples.