Solid-phase microextraction (SPME) has been evaluated for the recovery of explosives residues from aqueous samples and real post-explosion solid debris samples and optimized using gas chromatography with an electron capture detector (GC-ECD) and high-performance liquid chromatography with ultraviolet detection (HPLC-UV). A modified SPME/HPLC interface utilizing dual six-port valves allowed for independent optimization of SPME desorption and injection variables that provided improved chromatographic resolution and sensitivity. A unique combination of cyano and octadecyl columns resulted in the complete separation of the 14 explosives in EPA method 8330 mixture using HPLC with good quantitative results. At the optimum SPME conditions, the limits of detection (LOD) were found to be of 5 ng/mL to 16 ng/mL of explosives in water and 10 μg/kg to 40 μg/kg of explosives from soil. The technique has been successfully applied to the analysis of real post-explosion debris and can be adapted for use in the field utilizing portable chromatographic instruments.

Optimization of solid-phase microextraction (SPME) for the recovery of explosives from aqueous and post-explosion debris followed by gas and liquid chromatographic analysis

Application of High-Pressure Liquid Chromatography and Thermal Energy Analyzer to Analysis of Trinitroglycerin and Its Metabolites in Blood

A simple procedure has been developed for the determination of munitions present in water at levels as low as 0.1 /sup +/g/L. The method uses 60-80 mesh XAD-4 for extraction, followed by elution with 20 mL of ethyl acetate, concentration of the eluate, separation by capillary GC, and detection using electron capture. Contrived and field samples containing nitrobenzene, 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2,4,6-trinitrotoluene (TNT), and 1,3,5-trinitrohexahydro-1,3,5-triazine (RDX) have been tested successfully. The XAD-4 extraction in the field reduced the cost of transporting water samples to the laboratory where additional savings occurred because less solvent was used to elute the resin than was required for solvent extraction. Adsorption onto particulate matter, association with humic acids, resin capacity, resin polarity, and incomplete dissolution were examined as the most likely causes of the low recoveries for RDX when XAD-2 and XAD-7 resins were used. 10 references, 5 tables.

Determination of munitions in water using macroreticular resins

The thermal energy analyzer (TEA®), interfaced to both a gas and a high performance liquid chromatograph, has been shown to be selective to nitro-based explosives at a sensitivity of 4 to 5 pg injected on-column. Analyses of “real world” explosives, post-explosion debris, handswabs, and human plasma are presented. Because of the selectivity of the technique, there was no need for sample cleanup before analysis.

Picogram Analyses of Explosive Residues Using the Thermal Energy Analyzer (TEA

Determination of vasodilators and their metabolites in plasma by liquid chromatography with a nitrosyl-specific detector.

Liquid chromatographic determination of nitroglycerin products in waste waters

Ammonium and magnesium sulfites were tested for purifying crude TNT in comparison with the conventional (“sellite”) process using sodium sulfite. The magnesium process easily gave an acceptable product in better yield, of higher quality, and at lower estimated cost. Magnesium values suitable for recycle were recovered from the waste water by calcination. The ammonium process gave an acceptable product only under specific reaction conditions, but the waste water can be recovered by mixing it with TNT process spent sulfuric acid, thereby eliminating a calcination step.

G. R. Gibson

Papers

Liquid chromatographic determination of nitroglycerin products in waste waters

New Procedures for Purifying TNT