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Adducts of nerve agents in phosphate buffer and their hydrolysis

After our publication on the formation of buffer adducts of G-type nerve agents with buffer compounds like TRIS, TES or HEPES we now report in a new publication in the journal Toxicology Letters the formation of pyrophosphate-like adducts of Gagents with phosphate buffer. In contrast to the phosphodiesters formed for example with TRIS, the phosphate adducts are not resistant to hydrolysis. Their hydrolysis at pH 7.4 is slow and follows a pseudo-0th order kinetic. This leads to a complex mixture of phosphorus containing species in solution with changing concentrations over time. Therefore we recommend to avoid the use of phosphate buffer for analytical applications with G-type nerve agents.

Stable adducts of nerve agents with buffer compounds like TRIS and HEPES

A new publication in the Journal of Chromatography B describes the formation of stable adducts of nerve agents like Sarin, Soman or Cyclosarin and common buffer compounds like TRIS,TES or HEPES. The molecular structure of the adducts was determined by LC-ESI-MS/MS and NMR spectroscopy. They were found to be phosphodiesters (“O-adducts”). Alternative buffering compounds for the work with warfare agents are proposed.

Reaction monitoring with 1H-31P HSQC NMR spectroscopy

A new publication in Analytical and Bioanalytical chemistry describes the use of 1H-31P HSQC NMR spectroscopy to monitor the degradation of highly toxic organophosphorus compounds by the enzyme DFPase.The method can be used for methylphosphonates, a group of compounds including nerve agents sarin (GB), soman (GD), cyclosarin (GF) and also VX. The limit of quantitation (LOQ) of the method is around 100 μM when using a 400 MHz NMR spectrometer.

Reaction Monitoring with FTIR Spectroscopy

A new publication describes the use of in-situ FTIR spectroscopy to monitor the degradation of highly toxic organophosphorus compounds by the enzyme DFPase. The use of Attenuated Total Reflexion (ATR) allows direct meassurements in the reaction vessel without the need for cuvettes. In comparison to established methods the total reaction volume can be significantly reduced, which also leads to a substantial reduction in the required ammount of toxic substrate and therefore to an increase in work safety.