Study On Rapid Determination Of Environmental Pollutants Using High Field Asymmetric Waveform Ion Mobility Spectrometry

With the rapid development of social and industry,the pollution of environment is becoming increasingly serious.The rapid acquisition of pollutant species and pollution degree has become a hot issue of concern for government supervision departments,enterprises and the public.High-Field Asymmetric Wave form Ion Mobility Spectrometry?FAIMS?is one kind of analysis technology with high frequency and high amplitude asymmetric electric field to realize the detection of trace substances by ion separation and identification.FAIMS has broad application prospects in the field of environmental pollutants detection due to its advantages like high speed,high sensitivity,rich spectrum information,and easy miniaturization.In this paper,we studied the FAIMS technology and its application in the field of rapid detection of environmental pollutants are studied.The main work are as follows:Firstly,the current situation of environmental pollution and the types and hazards of environmental pollutants were introduced.At the same time,various ion mobility spectrometry and their applications in environmental field were reviewed.The theoretical model of the flat plate structure FAIMS analyzer were established by simulatingthe structural parameters and working conditions of the FAIMS analyzer with COMSOL software,which provides a theoretical guidance for the design and optimization of the FAIMS.The FAIMS analyzer with high precision and excellent electrical properties has been developed.In addition,the key working power and circuit of FAIMS are designed and fabricated.Finally,a prototype of FAIMS for environmental pollutant detection is built.Volatile Organic Compounds and ammonia as the main pollutants in air and water were harmful to human health.In this paper,a novel and rapid approach for field detection of VOCs and ammonia in air and water using UV-FAIMS at ambient temperature and pressure was developed.Benzene and p-xylene were chosen as samples to study the impact of the dispersion voltage and the carrier gas flow rate on the detection sensitivity of FAIMS.In addition,other factors such as the sample concentration and the signal-to-noise ratio of the UV-FAIMS system were investigated.For benzene,the values of?2 and?4were 2.05?10^-5Td^-22 and 2.25?10^-9Td^-4and for p-xylene,were4.94?10^-5Td^-22 and7.92?10^-9Td^-4,respectively.Our experiment results demonstrated that the detection limits of the UV-FAIMS for benzene and p-xylene were0.034?/m³and 0.0079?/m³,respectively.The position of characteristic ion peak of ammonia in water were acquired by comparing the characteristic compensation voltage?CV?of standard ammonia sample with that of trace amount ammonia in water.The relation between the position of ammonia characteristic ion peaks with different dispersion voltages?DV?were studied.The values of?2 and?4are3.04*10^-5Td^-2and-1.99*10^-9Td^-44 respectively.The different concentration of ammonia in water were measured and the limit of detection?LOD?of ammonia in water was studied.The LOD is 9?g/L with S/N ratio of 3.The results of this paper provide a rapid,non-pretreatment means for the detection of ammonia in water matrices.