QOPNA, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
J Chromatogr A. 2011 Jun 17;1218(24):3771-80. doi: 10.1016/j.chroma.2011.04.026. Epub 2011 Apr 16.
Allergic asthma represents an important public health issue with significant growth over the years, especially in the paediatric population. Exhaled breath is a non-invasive, easily performed and rapid method for obtaining samples from the lower respiratory tract. In the present manuscript, the metabolic volatile profiles of allergic asthma and control children were evaluated by headspace solid-phase microextraction combined with gas chromatography-quadrupole mass spectrometry (HS-SPME/GC-qMS). The lack of studies in breath of allergic asthmatic children by HS-SPME led to the development of an experimental design to optimize SPME parameters. To fulfil this objective, three important HS-SPME experimental parameters that influence the extraction efficiency, namely fibre coating, temperature and time extractions were considered. The selected conditions that promoted higher extraction efficiency corresponding to the higher GC peak areas and number of compounds were: DVB/CAR/PDMS coating fibre, 22 °C and 60 min as the extraction temperature and time, respectively. The suitability of two containers, 1L Tedlar® bags and BIOVOC®, for breath collection and intra-individual variability were also investigated. The developed methodology was then applied to the analysis of children exhaled breath with allergic asthma (35), from which 13 had also allergic rhinitis, and healthy control children (15), allowing to identify 44 volatiles distributed over the chemical families of alkanes (linear and ramified) ketones, aromatic hydrocarbons, aldehydes, acids, among others. Multivariate studies were performed by Partial Least Squares-Discriminant Analysis (PLS-DA) using a set of 28 selected metabolites and discrimination between allergic asthma and control children was attained with a classification rate of 88%. The allergic asthma paediatric population was characterized mainly by the compounds linked to oxidative stress, such as alkanes and aldehydes. Furthermore, more detailed information was achieved combining the volatile metabolic data, suggested by PLS-DA model, and clinical data.
变应性哮喘是一个重要的公共卫生问题，近年来其发病率显著上升，尤其是在儿科人群中。呼出气是一种非侵入性、易于操作且快速的方法，可从下呼吸道获取样本。在本手稿中，通过顶空固相微萃取结合气相色谱-四极杆质谱法（HS-SPME/GC-qMS）评估了变应性哮喘和对照儿童的代谢挥发性谱。由于缺乏变应性哮喘儿童呼出气的研究，因此开发了一种实验设计来优化 SPME 参数。为了实现这一目标，考虑了三个重要的 HS-SPME 实验参数，这些参数会影响萃取效率，即纤维涂层、温度和萃取时间。选择的条件可促进更高的萃取效率，对应更高的 GC 峰面积和化合物数量，分别为：DVB/CAR/PDMS 纤维涂层、22°C 和 60 分钟作为萃取温度和时间。还研究了两种容器，即 1L Tedlar®袋和 BIOVOC®，对呼吸收集和个体内变异性的适用性。然后将所开发的方法应用于分析患有变应性哮喘的儿童（35 名）的呼气，其中 13 名儿童也患有变应性鼻炎，以及健康对照儿童（15 名），从中鉴定出 44 种挥发性物质，分布在烷烃（直链和支链）、酮、芳烃、醛、酸等化学家族中。通过偏最小二乘判别分析（PLS-DA）进行了多变量研究，使用了一组 28 种选定的代谢物，并通过分类率为 88% 达到了区分变应性哮喘和对照儿童的效果。变应性哮喘儿科人群的特征主要是与氧化应激有关的化合物，如烷烃和醛类。此外，通过 PLS-DA 模型和临床数据相结合，还获得了更详细的信息。
