基于UV-FAIMS的挥发性氯代苯检测方法

摘要

Volatile chlorobenzenes (CBs)is an organic pollutant which exists ubiquitously in the environment.Ion Mobility Spectrometry (IMS)has been a powerful technique for quick ion-separation and detection under ambient pressure.In this paper, atmospheric chlorobenzene,p-dichlorobenzene,o-dichlorobenzene and m-dichlorobenzene were detected by a homemade Vacuum Ultraviolet Field Asymmetric Waveform Ion Mobility Spectrometry (UV-FAIMS).The CV-I spectra under different Dispersion Voltage (DV)were obtained,then the CV-DV fingerprints spectra of the four substances were synthetized.Base on the finger-print spectra,optimal separation and detection parameters of three isomers:dichlorobenzene,o-dichlorobenzene,m-dichloro-benzene were determined.The results showed that under the DV of 800 and 1000 V,three substances could be effectively iden-tified at CV of 20.4 V (DV=800 V),3.2 V(DV=800 V)and 11.9 V(DV=1000 V),respectively,by selecting the character-istic peaks.The influences of flow rate on FWHM and peak position of FAIMS spectrum were studied and the results provided a reference for flow optimization.The limit of detection (LOD)of UV-FAIMS investigated by using different concentrations of di-chlorobenzene at DV=450 V and CV=4.3V was lower than 0.05 mg·m-3 .This paper provides a rapid and accurate detection method for halogenated benzene pollutant and other isomers of benzene.%挥发性氯代苯是一类典型的环境有机污染物,离子迁移谱(IMS)是一种大气压下基于离子迁移率的快速现场检测技术.采用自制的真空紫外离子源-高场不对称波形离子迁移谱(UV-FAIMS),对空气中氯苯、对二氯苯、邻二氯苯、间二氯苯进行了检测.获取了不同分离电压条件下的CV-I谱图,并以此得到了四种物质的CV-DV指纹谱图.在指纹谱图支持下,设计了对二氯苯、邻二氯苯、间二氯苯三种同分异构体最优化分离检测参数,结果表明在800和1000 V的分离电压下,通过特征峰的选取,在补偿电压(CV)为20.4 V(DV=800 V),3.2 V(DV=800 V)和11.9 V(DV=1000 V)处三种物质的混合物可以得到有效的分离识别.研究了流速对谱图峰位置和峰形的影响,得到不同流速下灵敏度和识别精度关系,为优化流量的选取提供了依据.在特征识别前提下考察了DV=450 V条件下,CV=4.3 V的对二氯苯特征峰的UV-FAIMS检测限,结果高达0.05 mg·m-3.该研究为卤代苯等多同分异构体苯类环境污染物的快速高精度检测提供了一种方法参考.