Impacts of sampling-tube loss on quantitative analysis of gaseous semi-volatile organic compounds (SVOCs) using an SPME-based active sampler
Impacts of sampling-tube loss on quantitative analysis of gaseous semi-volatile organic compounds (SVOCs) using an SPME-based active sampler
复制标题
使用基于 SPME 的主动进样器，采样管损耗对气态半挥发性有机化合物 (SVOC) 定量分析的影响
DOI：
10.1016/j.chemosphere.2022.134780
复制
发表时间：
2022-05-05
期刊：
影响因子：
8.8
通讯作者：
Huang，Haibao
中科院分区：
文献类型：
--
作者：
Cao，Jianping;Xie，Siqi;Huang，Haibao
活性采样器广泛应用于气态半挥发性有机化合物(SVOCs)的定量测定。采样器的上游经常安装采样管，特别是用于分离颗粒相和气相SVOCs的有源采样器，以及基于固相微萃取(SPME)的新型有源采样器。然而，气态的SVOCs很容易被采样管吸附，这可能会对定量结果产生较大的误差。以固相微萃取有源采样器为例，建立了描述气态SVOCs采样管损失的传质模型。实验涉及六个SVOCs。模型预测(具有最合适的表面/空气分配系数的SVOCs)被发现与测量一致。模型预测和实验数据都表明，由于采样管的损失，测得的浓度明显低于实际浓度(低约60%)。采样管损失的持续时间(τe，分钟到天)随SVOCs的挥发度(蒸汽压，Vp)而变化，即LOGτ随logVp的增加而早期增加。该关系有助于根据SVOCs的挥发度确定消除(减少)采样管损失影响的采样策略。上述结论也适用于其他气态SVOCs活性采样器。然而，由于其他有源采样器的采样管的大小和形状与基于SPME的有源采样器的大小和形状不同，还需要进一步的研究来量化采样管损失的影响。相应的传质模型和实验程序可能需要适当的调整。
Active samplers are widely used in the quantification of gaseous semi-volatile organic compounds (SVOCs). A sampling tube is often assembled upstream of the sampler, especially in the active samplers used for separating the particle-phase and gas-phase SVOCs and in the newly-designed active sampler based on solid-phase microextraction (SPME). However, gaseous SVOCs can be easily adsorbed by the sampling tube, which may induce significant errors to the quantitative results. Taking the SPME-based active sampler as an example, a mass-transfer model was developed to characterize the sampling-tube loss of gaseous SVOCs. Experiments involving six SVOCs were conducted. The model predictions (with a best-fit surface/air partition coefficient of SVOCs) were found to be consistent with the measurements. Both model predictions and experimental data indicated that the measured concentrations were significantly lower than the actual concentration (around 60% lower) due to the sampling-tube loss. The duration of sampling-tube loss (τe, minutes to days) varied with the volatility of SVOCs (vapor pressure,Vp), i.e., logτelinearly increased as increasing logVp. The relationship could be helpful for determining the sampling strategies to eliminate (reduce) the effects of sampling-tube loss according to the volatility of SVOCs. The above conclusions may be also applicable for other active samplers of gaseous SVOCs. However, further studies are required to quantify the effects of sampling-tube loss for other active samplers due to the difference in the size and shape of the sampling tube between them and the SPME-based active sampler. The corresponding mass-transfer model and experimental procedure may require adjustment as appropriate.