Mobile phase influence on electrospray ionization for the analysis of smokeless powders by gradient reversed phase high-performance liquid chromatography-ESIMS.

The solution parameters associated with gradient elution reversed phase high-performance liquid chromatography (HPLC) were characterized by evaluating the electrospray ionization mass spectrometry (ESIMS) response of selected smokeless powder additives. Using direct liquid infusion, the positive ion ESIMS responses were determined for three general classes of powder constituents: dialkylphthalate acid esters, N,N'-dialkyl-N,N'-diphenyl urea based stabilizers and nitroso-, nitro-, and dinitro- derivatives of diphenylamine. The relative ESIMS intensities of the powder components were investigated as a function of three solution parameters: ammonium acetate concentration, pH, and percent methanol.

The analysis of high explosives by liquid chromatography/electrospray ionization mass spectrometry: multiplexed detection of negative ion adducts.

The negative ion electrospray ionization mass spectrometric (ESI-MS) detection of adducts of high explosives with chloride, formate, acetate, and nitrate was used to demonstrate the gas-phase interaction of neutral explosives with these anions. The relative intensities of the adduct species were determined to compare the competitive formation of the selected high explosives and anions. The relative stability of the adduct species varies, yielding preferential formation of certain anionic adducts with different high explosives.

Gradient reversed-phase liquid chromatographic-electrospray ionization mass spectrometric method for the comparison of smokeless powders.

A gradient reversed-phase liquid chromatographic-electrospray ionization mass spectrometric (LC-ESIMS) method was developed to determine compositional variation in the organic additives of smokeless powders. The method was optimized for the separation and detection of selected powder constituents, including diphenylamine, along with isomers of its nitroso and nitro derivatives, centralite I and II, in addition to dialkylphthalate acid esters. A series of commercially available smokeless powders was prepared by organic liquid extraction and characterized using the LC-ESIMS method.

Flame ionization detection after splitting the water effluent in subcritical water chromatography.

The coupling of subcritical water separation with flame ionization detection (FID) in the split mode has been investigated in this study. In order to keep the FID system stable during subcritical water separation, a Tee union was connected between the separation column and the FID system to split the water flow. The ratio of the water flow to the FID system over the flow-rate to a waste bottle varied depending on the dimension of capillary tubings and the total water flow-rate used.