色谱2026，Vol.44Issue(4)：453-466,14.DOI:10.3724/SP.J.1123.2025.07009
热脱附-气流调制全二维气相色谱-飞行时间质谱测定环境大气中中等挥发性有机物
Determination of atmospheric intermediate volatility organic compounds with thermal desorption-flow modulator comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry
摘要
Abstract
Atmospheric intermediate volatile organic compounds(IVOCs)are complex mixtures.Due to the limited separation and identification capabilities of one-dimensional gas chromatography(1D-GC),a large portion of atmospheric IVOCs—which often elute as unresolved or complex peaks—are categorized as an unspeciated complex mixture(UCM).This constrains the accurate ap-portionment of atmospheric IVOCs.To address this problem,an alternative analytical method has been developed utilizing thermal desorption-flow modulation comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(TD-FM GC×GC-TOF MS)to measure atmospheric IVOCs.Analytical optimization focused on fill and flush time within a 3-second modulation period,with optimal values determined as 2 870 ms and 130 ms,respectively,to maximize separation efficiency and signal response.Compounds were separated on a ZB-5HT column(20 m×0.18 mm×0.18 μm)as the first dimension,with a BP-50 column(5 m×0.25 mm×0.20 μm)serving as the second dimension.Helium was employed as the carrier gas with column pressures maintained at 254.4 kPa(first dimension)and 202.1 kPa(second dimension).The following temperature program was used:50℃for 10 min,then increased to 300℃at 10℃/min,with the final temperature held for 20 min.The MS was operated in electron impact(EI,70 eV)ionization mode.Both the ion source and transfer line temperatures were set at 300℃.MS signals were re-corded in full scan mode with a scan range of m/z 40 to m/z 800.During thermal desorption,the desorption temperature was set at 320℃,and the cold trap temperature was maintained at-10℃to capture desorbed targets.The secondary desorption flow rate was set at 16 mL/min.Under these optimized conditions,the method demonstrated acceptable linearity,with correlation coefficients ranging from 0.922 3 to 0.998 4,for 69 selected targets spanning 1 to 20 ng/tube,with method detection limits(spiked at 1 ng/tube)between 0.010 7 and 0.410 1 ng/m3,with recoveries ranging from 80.4%to 136.0%.Relative standard deviation values among replicate samples(n=7)spiked at 1 ng/tube,3 ng/tube,and 10 ng/tube levels were around 4.5%-33.9%,3.2%-19.9%and 3.5%-18.6%,respectively.Application of the method to atmospheric IVOC samples collected from an urban site of Shanghai,revealed total IVOCs mass concentrations of 8.6-61.1 μg/m3.Of these,mass con-centrations of 853 individual species identified by the present method comprised 96.2%of total IVOCs.Consequently,the newly developed method improved the identification rate for UCM.Importantly,the newly speciated aromatics,chlorinated IVOCs,and oxygenated IVOCs exhibited different emission sources distinct from those routinely monitored compounds.Therefore,this study es-tablished a reliable method for determining atmospheric IVOCs,offering strong data support for precise source apportionment of complex IVOCs in the atmosphere.Additionally,this method can be used to monitor IVOCs across various environmental metrics,thereby providing essential data to support the management and control of these compounds.关键词
热脱附/气流调制/全二维气相色谱/飞行时间质谱/中等挥发性有机物/环境大气Key words
thermal desorption/flow modulation/comprehensive two-dimensional gas chroma-tography(GC×GC)/time-of-flight mass spectrometry(TOF-MS)/intermediate volatility organic compounds(IVOCs)/ambient atmosphere分类
化学化工引用本文复制引用
汪睿,李英杰,王佳华,马长文,蒋家奎..热脱附-气流调制全二维气相色谱-飞行时间质谱测定环境大气中中等挥发性有机物[J].色谱,2026,44(4):453-466,14.基金项目
国家重点研发计划项目(2022YFC3703504) （2022YFC3703504）
上海市自然科学基金(22ZR1453200). National Key Research and Development Program of China(No.2022YFC3703504) （22ZR1453200）
Natural Science Foundation of Shanghai(No.22ZR1453200). （No.22ZR1453200）
