Criado-García L, Arce L, Valcárcel M
Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain.
Department of Analytical Chemistry, Annex C-3 Building, Campus of Rabanales, Institute of Fine Chemistry and Nanochemistry, University of Córdoba, 14071 Córdoba, Spain.
J Chromatogr A. 2016 Jan 29;1431:55-63. doi: 10.1016/j.chroma.2015.12.091. Epub 2016 Jan 6.
UV-ion mobility spectrometry (UV-IMS) is a reliable and inexpensive technique which allows efficient monitoring of BTX (benzene, toluene, m-xylene, o-xylene and p-xylene) in different air samples. Water molecules are unavoidably present in every on-field measurement affecting sensitivity and selectivity of the UV-IMS method. For this reason, the influence of humidity on the mobility spectra when measuring BTX is discussed here. Furthermore, a polydimethyl siloxane (PDMS) membrane assembled on an ad-hoc designed membrane holder coupled to UV-IMS was proposed for online measurement of analytes in humid gaseous samples without sample preparation/pre-treatment steps. The use of this membrane reduces the moisture of the gaseous sample before entering into the IMS, and the consequent distortion of the signal. The limit of detection (LOD) and the limit of quantification (LOQ) achieved with the method proposed were in the range of 0.49-1.21mgL(-1) and 1.63-4.03mgL(-1), respectively for all analytes. The precision of the method was evaluated in terms of repeatability and reproducibility obtaining values lower than 1.1% for drift time and 12.0% for peak height when the membrane was used coupled to the UV-IMS for all target analytes in the humidity range of 10-75% RH. Thus, BTX can be determined directly and quantified unequivocally with the membrane system in ambient air even at humid condition.
紫外离子迁移谱（UV-IMS）是一种可靠且经济的技术，可用于有效监测不同空气样本中的BTX（苯、甲苯、间二甲苯、邻二甲苯和对二甲苯）。在每次现场测量中，水分子不可避免地会存在，这会影响UV-IMS方法的灵敏度和选择性。因此，本文讨论了湿度对测量BTX时迁移谱的影响。此外，还提出了一种组装在专门设计的膜支架上的聚二甲基硅氧烷（PDMS）膜，该膜与UV-IMS相连，用于在无需样品制备/预处理步骤的情况下在线测量潮湿气态样品中的分析物。使用这种膜可在气态样品进入离子迁移谱之前降低其水分含量，从而避免信号失真。所提出的方法实现的检测限（LOD）和定量限（LOQ）对于所有分析物分别在0.49 - 1.21mgL⁻¹和1.63 - 4.03mgL⁻¹范围内。当膜与UV-IMS联用，在10 - 75%相对湿度范围内对所有目标分析物进行测量时，该方法的精密度通过重复性和再现性进行评估，漂移时间的精密度值低于1.1%，峰高的精密度值低于12.0%。因此，即使在潮湿条件下，使用该膜系统也可直接测定环境空气中的BTX并进行明确的定量。
