Université d'Aix-Marseille I, II, III-CNRS, UMR 6264, Laboratoire Chimie Provence, Equipe Instrumentation et Réactivité Atmosphérique, Case courrier 29, 3 place Victor Hugo, F-13331 Marseille Cedex 3, France.
Talanta. 2012 Jan 15;88:252-8. doi: 10.1016/j.talanta.2011.10.039. Epub 2011 Oct 31.
A characterisation of a system designed for active sampling of gaseous compounds with Solid Phase Microextraction (SPME) fibres is described. This form of sampling is useful to automate sampling while considerably reducing the sampling times. However, the efficiency of this form of sampling is also prone to be affected by certain undesirable effects such as fibre saturation, competition or displacement effects between analytes, to which particular attention should be paid especially at high flow rates. Yet, the effect of different parameters on the quantitivity of the results has not been evaluated. For this reason, in this study a careful characterisation of the influence of the parameters involved in active sampling SPME has been performed. A versatile experimental set-up has been designed to test the influence of air velocities and fluid regime on the quantitivity and reproducibility of the results. The mathematical model applied to the calculation of physical parameters at the sampling points takes into consideration the inherent characteristics of gases, distinctive from liquids and makes use of easily determined experimental variables as initial/boundary conditions to get the model started. The studies were carried out in the high-volume outdoor environmental chambers, EUPHORE. The sample subjected to study was a mixture of three aldehydes: pentanal, hexanal and heptanal and the determination methodology was O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine hydrochloride (PFBHA) on-fibre derivatisation. The present work proves that the determination procedure is quantitative and sensitive, independent from experimental conditions: temperature, relative humidity or ozone levels. With our methodology, the influence on adsorption of three inter-related variables, i.e., air velocity, flow rate and Reynolds numbers can be separated, since a change can be exerted in one of them while keeping the others constant.
描述了一种用于使用固相微萃取（SPME）纤维对气态化合物进行主动采样的系统的特性。这种采样形式有助于实现采样自动化，同时大大减少采样时间。然而，这种采样形式的效率也容易受到某些不良影响的影响，例如纤维饱和、分析物之间的竞争或置换效应，因此尤其需要特别注意高流速。然而，尚未评估不同参数对结果定量的影响。出于这个原因，在这项研究中，对主动采样 SPME 中涉及的参数的影响进行了仔细的表征。设计了一种多功能实验装置，以测试空气速度和流体状态对结果定量和重现性的影响。应用于采样点物理参数计算的数学模型考虑了气体的固有特性，与液体不同，并利用易于确定的实验变量作为初始/边界条件来启动模型。研究在高容量户外环境室 EUPHORE 中进行。研究的样品是三种醛的混合物：戊醛、己醛和庚醛，测定方法是 O-(2,3,4,5,6-五氟苄基）-羟胺盐酸盐（PFBHA）纤维上衍生化。本工作证明，该测定程序是定量和敏感的，与实验条件无关：温度、相对湿度或臭氧水平。使用我们的方法，可以分离三个相互关联的变量（即空气速度、流速和雷诺数）对吸附的影响，因为可以在保持其他变量不变的情况下改变其中一个变量。
