Development Of Reference Materials For BTEX In Groundwater Simulation Matrix

Water based organic standard samples refer to organic standard samples based on natural water environment or artificial simulated water environment.Due to the complexity of the water matrix in the natural environment,there are a lot of suspended particles,microorganisms and some inorganic substances in the water.The existence of these substances may have various adsorption,complexation and degradation effects on the organic matter in the water,so it is difficult to ensure the uniformity and stability of the organic matter in the water,As a result,there is no real water-based organic standard sample at home and abroad.At present,the organic pollution of groundwater is becoming more and more obvious in China,and the detection rate of volatile organic compounds is higher.It is of great significance to develop volatile organic compounds reference materials similar to groundwater matrix.The development of groundwater matrix VOC reference materials can not only reduce the impact of groundwater matrix on the test,make the VOC test results more accurate,more intuitive show the true content of VOC in groundwater environment,and facilitate the implementation of accurate environmental monitoring and pollution control.In this paper,11 kinds of volatile organic compounds（VOCs）reference materials were prepared by adding VOCs standard solution to simulated groundwater matrix（1）The relative expanded uncertainty of 11 volatile organic compounds is 0.107～0.182under the condition of k=2 and 95%confidence probability.（2）The typical groundwater HCO₃-Ca in North China Plain is selected as the research object of simulated groundwater matrix.The effects of TDS and fulvic acid on 11 kinds of volatile organic compounds（VOCs）in underground water were studied.The results showed that fulvic acid<100 mg/L and total dissolved solids<2000 mg/l had no significant effect.（3）The effects of methanol（0.4%,0.8%,1.2%,1.6%,2.0%）and ascorbic acid（0.5%,1%,2%,3%,4%）on 11 kinds of volatile organic compounds（VOCs）in underground water were studied.The results showed that methanol（0.8%）and ascorbic acid（4.0%）had no obvious effect.（4）RM₁,RM₂and RM₃were prepared,and their homogeneity and stability were evaluated.The results showed that the homogeneity of the sample was good;When the sample was stored at 4℃,its characteristic value remained stable within 12 months,and formed a technical method for the development of VOC reference materials in simulated groundwater matrix.