Isolation of the anionic toxin monofluoroacetate from a decontamination foam matrix

摘要

Oxidizing decontamination agents such as the Vanguard-Allen CASCAD foam can be used to contain the blast from an improvised explosive device and can also be used to decontaminate conventional chemical weapons via hydrolysis or oxidation reactions. However, chemical analysis of such foams remains a challenge due to complex sample matrices that can contain chlorine bleaches (such as dichloroisocyanurate), co-solvents, and surfactants. To overcome this issue, we have developed a combined liquid-liquid extraction and solid phase extraction (SPE) protocol that isolates toxicologically relevant anionic analytes, such as monofluoroacetate (CH2FCO2-), from such a matrix. The protocol development was monitored by H-1 decoupled F-19 NMR spectroscopy, which gave a limit of detection of 0.1 mM for CH2FCO2- using a 20 min acquisition time. After separation using a strong anion exchange (SAX) SPE column and an eluent of 10% ammonia in methanol, the analyte was derivatised using 2,4-dichloroaniline and dicyclohexylcarbodiimide (DCC) before GC-MS analysis. This resulted in a limit of detection of 5.9 mu M for monofluoroacetate in a CASCAD decontamination foam matrix.