RESUMO
MEKC has been used in conjunction with UV detection for identification and quantitation of high explosives in environmental samples. To ensure the compatibility of the technique with ESI-MS, perfluorooctanoic acid (PFOA), a volatile micelle, was used. Separation of EPA Method 8330 Mixes A and B using various concentrations of the micelle showed that the 80 mM solution of PFOA was the optimum concentration for the separation of the explosives. MEKC analysis of explosives with ESI-MS under optimum micelle concentration provided excellent results indicating the compatibility of the method with ESI-MS. Finally, the MEKC-UV method was applied to the detection and quantitation of explosives in various environmental samples including water, sand, and soil. The results demonstrate that the MEKC method described herein is a viable technique for detection of explosives in environmental samples using UV detection, while maintaining the compatibility of the technique with MS detection without any modification to the separation method, if laboratories decided to pursue this route in the future.
Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Poluentes Ambientais/análise , Poluentes Ambientais/isolamento & purificação , Substâncias Explosivas/análise , Substâncias Explosivas/isolamento & purificação , Caprilatos/análise , Caprilatos/química , Caprilatos/isolamento & purificação , Poluentes Ambientais/química , Substâncias Explosivas/química , Fluorocarbonos/análise , Fluorocarbonos/química , Fluorocarbonos/isolamento & purificação , Limite de Detecção , Micelas , Solo/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Água/químicaRESUMO
To address the need for the forensic analysis of high explosives, a novel capillary electrophoresis mass spectrometry (CE-MS) technique has been developed for high resolution, sensitivity, and mass accuracy detection of these compounds. The technique uses perfluorooctanoic acid (PFOA) as both a micellar electrokinetic chromatography (MEKC) reagent for separation of neutral explosives and as the complexation reagent for mass spectrometric detection of PFOA-explosive complexes in the negative ion mode. High explosives that formed complexes with PFOA included RDX, HMX, tetryl, and PETN. Some nitroaromatics were detected as molecular ions. Detection limits in the high parts per billion range and linear calibration responses over two orders of magnitude were obtained. For proof of concept, the technique was applied to the quantitative analysis of high explosives in sand samples.
