The analysis of black powder substitutes containing ascorbic acid by ion chromatography/mass spectrometry.
ABSTRACT Black powder substitutes containing ascorbic acid are a group of low explosives that utilize ascorbic acid as the fuel. The analysis of these powders is complicated by the degradation of ascorbic acid which occurs rapidly in solution and may also occur as the powder ages. Aqueous extracts of both intact powders and postblast residues were analyzed by an existing ion chromatography/mass spectrometry (IC/MS) method used at the Bureau of Alcohol, Tobacco, Firearms and Explosives. Results have shown that while ascorbic acid itself is not detected in this method, its diagnostic degradation products (threonic acid, monohydrated diketogulonic acid, and oxalic acid) can be identified. In addition, anions from the inorganic oxidizers (perchlorate and nitrate) and combustion products such as chloride, chlorate, and nitrite, can be identified within the same experiment. While this IC/MS method shows promise, future modifications are necessary because of limitations in identifying threonate in postblast residues, as well as coeluting compounds observed in postblast residues.
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ABSTRACT: The hydrolysis of dehydroascorbic acid (DAAH) at neutral pH and 27 degrees C was investigated by direct infusion electrospray ionisation ion trap mass spectrometry (ESI-MS). This approach permitted derivatisation and elution procedures to be avoided, reducing to the minimum extent sample manipulation and allowing a rapid and direct observation of the species involved in the reaction. Six main peaks, related to hydrated dehydroascorbate (HyDAA-) and diketogulonate (HyDKG-) anions, were observed in the mass spectra of DAAH solutions at different times of incubation and were characterised by MSn experiments. The relevant signal intensities changed with time and a model, based on the irreversible pseudo-first order HyDAA(-)-->HyDKG- conversion, fitted successfully the data obtained for dehydroascorbate. The kinetic constant of the process was (3.2 +/- 0.5) x 10(-2) min-1. The influence of metal ion traces on the hydrolysis rate was also checked, performing experiments in the presence of EDTA, and was found to be negligible.The Analyst 01/2001; 125(12):2244-8. · 3.97 Impact Factor
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ABSTRACT: 1. Previously, we reported that calcium L-threonate caused a dose-related increase in uptake of ascorbic acid (AA) by human T-lymphoma cells. Preincubation of mouse fibroblasts with calcium L-threonate also resulted in a dose-related augmentation in uptake of AA as compared to non-treated controls. 2. Potassium L-lyxonate increased AA uptake by lymphoma cells, but did not significantly affect uptake by fibroblasts. Tartaric acid decreased uptake of AA by both cell lines. 3. Ouabain and dinitrophenol had no effect on AA uptake nor on the ability of threonate to augment AA uptake by fibroblasts. However, in T-lymphoma cells ouabain and dinitrophenol reduced AA uptake and prevented augmentation of AA uptake by calcium L-threonate.General Pharmacology 12/1994; 25(7):1465-9.
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ABSTRACT: We have previously shown that vitamin C (ascorbic acid) can initiate hydroxyl radical formation in copper contaminated household drinking water. In the present study, we have examined the stability of vitamin C in copper and bicarbonate containing household drinking water. In drinking water samples, contaminated with copper from the pipes and buffered with bicarbonate, 35% of the added vitamin C was oxidized to dehydroascorbic acid within 15 min. After 3h incubation at room temperature, 93% of the added (2 mM) ascorbic acid had been oxidized. The dehydroascorbic acid formed was further decomposed to oxalic acid and threonic acid by the hydrogen peroxide generated from the copper (I) autooxidation in the presence of oxygen. A very modest oxidation of vitamin C occurred in Milli-Q water and in household water samples not contaminated by copper ions. Moreover, addition of vitamin C to commercially sold domestic bottled water samples did not result in vitamin C oxidation. Our results demonstrate that ascorbic acid is rapidly oxidized to dehydroascorbic acid and further decomposed to oxalic- and threonic acid in copper contaminated household tap water that is buffered with bicarbonate. The impact of consuming ascorbic acid together with copper and bicarbonate containing drinking water on human health is discussed.Free Radical Research 09/2004; 38(8):855-60. · 3.28 Impact Factor