ИСТИНА

The Chemical Weapons Convention (CWC) is an arms control treaty which outlaws the production, stockpiling, and use of chemical weapons and their precursors [1]. The treaty entered into force in 1997. As of October 2013, 190 states have given their consent to be bound by the CWC. However, to date some chemical warfare agents (CWA) were used in local armed conflicts and terrorist attacks. Also big stocks of CWA are still stored worldwide. Nerve agents are rather volatile and easy to degrade. Once exposed to the environment nerve agents readily degrade by rapid hydrolysis to the corresponding alkyl methylphosphonic acids (AMPAs) which never exist in nature. These alkyl methylphosphonic acids are finally slowly hydrolyzed to methylphosphonic acid (MPA). Methylphosphonic acid is the most stable hydrolysis product of organophosphate nerve agents, which persist in environmental samples for a long time. A highly sensitive method of methylphosphonic acid and other AMPAs detection in environmental waters has been developed and validated. Derivatization process and stability of p-bromophenacyl bromide methylphosphonic acid derivate were studied. The fact that AMPAs unlike MPA did not react with p-bromophenacyl bromide under chosen conditions was discovered. Derivate was stable for 2 days and water content no greater than 7% didn’t influence the reaction yield. The analytes concentration step in a rotary evaporator was employed prior to analysis. Detection of the pre-column methylphosphonic acid derivatization product and AMPAs was carried out using tandem mass spectrometry with electrospray ionization after hydrophilic interaction liquid chromatography separation. Evaporation recoveries of 90% for MPA, 94% for ethyl methylphosphonic acid (EMPA), 97% for i-propyl methylphosphonic acid (IPMPA), 98% for i-butyl methylphosphonic acid (IBMPA), 93% for pinacolyl methylphosphonic acid (PMPA) were obtained. The intraday and interday repeatability were 6% and 25% for MPA, 5% and 15% for EMPA, 7% and 17% for IPMPA, 6% and 20% for IBMPA, 9% and 14 % for PMPA correspondingly. The hydrophilic interaction chromatography method results in excellent peak shape at adequate retention time. Developed approach successfully combines relatively fast derivatization and sample preparation with hydrophilic interaction chromatography and tandem mass spectrometry which allows to achieve ultra-low limits of detection 0.2 ng mL-1 for MPA, 50 pg mL-1 for EMPA, 10 pg mL-1 for IPMPA, 5 pg mL-1 for IBMPA, 5 pg mL-1 for PMPA in the stone extracts. Developed approach was successfully applied for environmental samples from decommissioned plant for the production of chemical weapons.