Llompart M, Li K, Fingas M
Departamento de Quimica Analitica Nutricion y Bromatologia, Facultad de Quimica, Universidad de Santiago de Compostela, E-15706 Santiago de Compostela, Spain.
Talanta. 1999 Feb;48(2):451-9. doi: 10.1016/s0039-9140(98)00263-x.
We have investigated the use of headspace solid phase microextraction (HSSPME) as a sample concentration and preparation technique for the analysis of volatile and semivolatile pollutants in soil samples. Soil samples were suspended in solvent and the SPME fibre suspended in the headspace above the slurry. Finally, the fibre was desorbed in the Gas Chromatograph (GC) injection port and the analysis of the samples was carried out. Since the transfer of contaminants from the soil to the SPME fibre involves four separate phases (soil-solvent-headspace and fibre coating), parameters affecting the distribution of the analytes were investigated. Using a well-aged artificially spiked garden soil, different solvents (both organic and aqueous) were used to enhance the release of the contaminants from the solid matrix to the headspace. It was found that simple addition of water is adequate for the purpose of analysing the target volatile organic chemicals (VOCs) in soil. The addition of 1 ml of water to 1 g of soil yielded maximum response. Without water addition, the target VOCs were almost not released from the matrix and a poor response was observed. The effect of headspace volume on response as well as the addition of salt were also investigated. Comparison studies between conventional static headspace (HS) at high temperature (95 degrees C) and the new technology HSSPME at room temperature ( approximately 20 degrees C) were performed. The results obtained with both techniques were in good agreement. HSSPME precision and linearity were found to be better than automated headspace method and HSSPME also produced a significant enhancement in response. The detection and quantification limits for the target VOCs in soils were in the sub-ng g(-1) level. Finally, we tried to extend the applicability of the method to the analysis of semivolatiles. For these studies, two natural soils contaminated with diesel fuel and wood preservative, as well as a standard urban dust contaminated with polyaromatic hydrocarbons (PAHs) were tested. Discrimination in the response for the heaviest compounds studied was clearly observed, due to the poor partition in the headspace and to the slow kinetics of all the processes involved in HSSPME.
我们研究了顶空固相微萃取（HSSPME）作为一种样品浓缩和制备技术，用于分析土壤样品中的挥发性和半挥发性污染物。将土壤样品悬浮于溶剂中，SPME纤维悬浮于浆液上方的顶空中。最后，将纤维在气相色谱（GC）进样口中解吸，并对样品进行分析。由于污染物从土壤转移至SPME纤维涉及四个独立相（土壤-溶剂-顶空和纤维涂层），因此研究了影响分析物分布的参数。使用一种充分老化的人工加标花园土壤，采用不同的溶剂（有机和水性）来增强污染物从固体基质向顶空的释放。结果发现，简单加水就足以用于分析土壤中的目标挥发性有机化合物（VOCs）。向1克土壤中加入1毫升水可产生最大响应。不加水时，目标VOCs几乎不从基质中释放出来，响应较差。还研究了顶空体积对响应的影响以及盐的添加。进行了高温（95℃）下传统静态顶空（HS）与室温（约20℃）下新技术HSSPME之间的比较研究。两种技术获得的结果吻合良好。发现HSSPME的精密度和线性优于自动顶空法，且HSSPME的响应也有显著增强。土壤中目标VOCs的检测限和定量限处于亚纳克/克（-1）水平。最后，我们试图将该方法的适用性扩展至半挥发性物质的分析。对于这些研究，测试了两种受柴油燃料和木材防腐剂污染的天然土壤，以及一种受多环芳烃（PAHs）污染的标准城市灰尘。由于顶空中分配不佳以及HSSPME中所有相关过程的动力学缓慢，在所研究的最重化合物的响应中明显观察到了差异。
