|
| Determination of Degradation Rate of Zirconium Hydroxide on VX by Gas Chromatography Coupled with Aqueous Phase Termination－Solvent Extraction |
| |
| View Full Text Download reader |
| DOI： |
| KeyWord:zirconium hydroxide VX degradation rate gas chromatography |
| Author | Institution |
| HUANG Xing-qi，ZHAO Ting，YAN Chun-xiao，JIN Yan-ren，ZHANG Hong-peng，HU Xiao-chun，WU Yue |
1. Institute of NBC Defense，Chinese People's Liberation Army，Beijing ，China; 2. Shanxi Xinhua Chemical Defense Equipment Research Institute Co.，Ltd.，Taiyuan ，China |
|
| Hits: 1040 |
| Download times: 371 |
| Abstract: |
| VX（O-Ethyl S-（2-diisopropylamino） ethyl methylphosphonothiolate） is one of nerve agents with high toxicity，which could easily penetrate into the skin．Once being poisoned，the normal conduction function of the nervous system might be destroyed in a short time，causing breathing difficulties，severe convulsions，loss of consciousness and other symptoms．The most horrible thing is that only a few milligrams of VX could cause death．In 2017，Kim Jong Nam，the eldest brother of North Korea's top leader，died of this poison，which had attracted a great concern all over the world．Studies have shown that zirconium hydroxide could effectively hydrolyze VX through basic t-OH and acidic b-OH．In this study，an analytical method was established for the determination of the degradation rate of zirconium hydroxide powder on VX by gas chromatography with flame photometric detector coupled with aqueous phase termination－solvent extraction．Qualitative analysis and quantitative analysis were depended on retention time and internal standard method respectively．The pretreatment method for liquid－solid decontamination samples was optimized．The effects of extractants，including n-hexane and dichloromethane，extraction methods，such as ultrasound and oscillation，terminators，and standing time on the recovery of VX were investigated．Gas chromatography was used to detect the internal standard and VX，with the retention times of 11.603 min and 12.080 min，respectively．Generally，terminators are used in the degradation process to achieve the purpose of eliminating the activity of decontaminants．However，the most critical thing in this system is to select a terminator that could make the unreacted VX desorb from the adsorption sites of Zr（OH）4．Acidic substances may react with VX to form salt，increasing its solubility in water and making it difficult to extract it into the organic phase. Strong alkaline substances have a degradation reaction with VX．As a result，weak alkaline substances are suitable for termination．It was found that the borax buffer solution has a stable pH value and the best termination effect．Experimental results showed that the sample，which was terminated with 10 mL of 0.05 mol/L borax aqueous solution，extracted with 50 mL of dichloromethane，shaking for 20 s and standing for 10 min，had the best extraction rate．The recovery reached to 87.8%－90.3%，with the relative standard deviation（RSD） not more than 1.2%．Within the range of 9.7－388.0 μg/mL，there existed a good linear relationship for VX degradation rate with a correlation coefficient of 0.996 9．The detection limit（LOD） and the quantitation limit（LOQ） of this method were 0.05 μg/mL and 0.15 μg/mL，respectively．Using the optimized method，the degradation rate for VX variation time was investigated，which conformed to the pseudo－first－order kinetic process，and the reaction rate constant（k） was 0.019 2 min－1．With a simple，rapid and safe pretreatment，high sensitivity and accuracy，the method provides a reference for evaluation of the decontamination reaction of amphoteric hydroxide substances． |
| Close |