Improved tert-Butyldimethylsilylation Gas Chromatographic/Mass Spectrometric Detection of Nerve Gas Hydrolysis Products from Soils by Pretreatment of Aqueous Alkaline Extraction and Strong Anion-Exchange Solid-Phase Extraction

Abstract

In the analysis of tert-butyldimethylsilyl derivatives (IBDMS) of alkyl methylphosphonic acids (RMPA) and methylphosphonic acid (MPA), from soils by gas chromatography/mass spectrometry (GC/MS), the detection yields are generally low, due to the suppression of TBDMS derivatization by the soil matrix components and the adsorption of RMPA and MPA to the soils. An ion-exchange pretreatment of the aqueous soil extract can be used to overcome the former factor by removing interfering compounds. A pretreatment method is described for improving the detection yields due to the latter factor, using an alkaline extraction procedure. The recovery was estimated quantitatively using capillary electrophoresis. The soil samples tested included volcanogenous immature soils and showed a low aqueous extraction recovery and GC/MS detection yields. The inclusion of sodium hydroxide in the extraction solvent dramatically increased the recovery. Using a 0.1 M sodium hydroxide solution, the recovery was in excess of 68%. Interfering components were removed from the alkaline soil extract by solid-phase extraction of the acids on a silica-based strong anion exchanger. The alkaline soil extract was neutralized with hydrofluoric acid and applied to the cartridge in the fluoride form. After washing with water, MPA and RMPA could be eluted with methanolic ammonia nearly quantitatively. Using the established pretreatment method, MPA and RMPA were detected from all the soil samples in more than 67% yield.

The determination of organophosphonate nerve agent metabolites in human urine by hydrophilic interaction liquid chromatography tandem mass spectrometry

“…Quantification of phases I and II metabolites of chemical warfare agents by gas chromatography or liquid chromatography, coupled with mass spectrometric detection, is the historic and most common approach for this assessment [2][3][4][5][6][7][8][9], although other detectors have been employed [10]. Researchers are also investigating the detection of chemical warfare agents and their degradation products in environmental samples [11][12][13][14][15]. Some researchers also employ various detector strategies in the absence of a chromatographic separation [16][17][18].…”

Appendix C. Collection of Samples for Chemical Agent Analysis

“…For example, liquid chromatography/mass spectrometry can be used to determine VX degradation products (Love 2004) and sulfur mustard degradation products (Creasy 1999). Various chemical reactions to form volatile derivatives of agent degradation products followed by analysis by gas chromatography/mass spectrometry or gas chromatography/flame photometric detection is another strategy that can be successfully used to detect agent degradation products (Creasy 1999, Purdon 1989, Naomi 2002, Black 2003 Table 5. AEGL 8-24 hr -Acute Exposure Guidelines; these values have been extrapolated for 24 hour exposure from AEGL-1 8 hr values for the purpose of this report; d.l.…”

Laboratory Identification of the Nerve Gas Hydrolysis Products Alkyl Methylphosphonic Acids and Methylphosphonic Acid, by Gas Chromatography-mass Spectrometry after <i>tert</i>-Butyldimethylsilylation

“…We attempted to break the binding of phosphonates onto the soil under elevated pH conditions by 0.1 M sodium hydroxide (NaOH). 42) The soil alkaline extract was neutralized with The recovery values were obtained after aqueous extraction and directly subjected to CE analysis and represent averages (n = 3). hydrofluoric acid, subjected to SPE, and analyzed by TBDMS GC-MS. Figure 7 indicates the yields of RMPAs and MPA by TBDMS GC-MS detection from soil samples combined with neutral (water) or alkali aqueous soil extraction and SPE pretreatment.…”