Choice and Evaluation of Chromatographic Determination Regimes of Bis(2-N,N-dialkylaminoethyl)disulfides Using Mass Spectrometry

Abstract

The article is dedicated to the elaboration of highly sensitive method for the detection of bis(2-N,Ndialkylaminoethyl)disulfides – hydrolysis (degradation) products of highly toxic organophosphorus nerve agents like VX and their analogues. These compounds are subject to the complete prohibition and destruction in accordance with the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction. Thus their detection is of great importance for the monitoring of the compliance with the Convention. The search for the optimum conditions for the chromatographic separation and mass-selective detection for these compounds is based on the OPCW recommendations for the annual international Proficiency Tests. We use gas chromatography as a separation technique. The objects of the research are the homologous organic compounds – bis(2-N,N-diisopropylaminoethyl)disulfide (hydrolysis product of VX-gas) and bis(2-N,N-diethylaminoethyl)disulfide (hydrolysis product of VR-gas). The optimum way of sample preparation is the organic extraction of disulfides from aqueous solution using methylene chloride. During the practical experiments we found out that the most sensitive devices for the detection of bis(2-N,N-dialkylaminoethyl)disulfides were the gas chromatograph Agilent 7890A together with the mass selective detector Agilent 7000B GC/MS Triple Quad and the licenced software Mass Hunter Workstation Software, Qualitative and Quantitative Analysis, version B.04.00. Using the proposed approach, the detection limits of bis(2-N,N-diisopropylaminoethyl) disulfide and bis(2-N,N-diethylaminoethyl)disulfide in water bodies were found to be 0,533±0,003 ng/ml, and 0,68±0,002 ng/ml, respectively.

Keywords

• convention
• mass spectrometric detection
• poisonous substances
• sample preparation
• toxic chemicals
• chemical weapons
• chromatographic peak
• chromatographic separation
• environmental study