Laboratory of Analytical Chemistry, Department of Chemistry, P.O. Box 55, FI-00014, University of Helsinki, Finland.
Talanta. 2010 Jan 15;80(3):1170-6. doi: 10.1016/j.talanta.2009.09.004.
Atmospheric aerosol particles, collected with the particle-into-liquid sampler at SMEARII station in Finland in mid-August 2007, were analysed for biogenic acids. The sample pretreatment method, comprising solid-phase extraction with anion exchange and hydrophilic-lipophilic balance materials, was optimized. Extraction efficiencies of solid-phase extraction from 10 and 20ml samples were about 100%, with average relative standard deviation of 8.9%, in concentration range from 12.5 to 50ng/ml of the acid. Extraction of aldehydes was less successful, with efficiencies from 69 to 163% and average 10% deviation. Pretreated samples were analysed by reversed phase high performance liquid chromatography with ion trap mass spectrometric detection. Limits of detection achieved for organic acids with the analytical procedure developed ranged from 9 to 27microg/l of extracted sample, while limits of quantitation were from 31 to 90microg/l. Oxidation with ozone was used for the preparation of the acid of beta-caryophyllene (beta-caryophyllinic acid), which was also studied in aerosol samples. MS(2) experiments were used to confirm the identification of trans-pinic, trans-pinonic and beta-caryophyllinic acids. Azelaic, hexadecanoic, cis-pinonic, and cis- and trans-pinic acids were quantitated in the samples with use of authentic standards, while the concentrations of trans-pinonic and beta-caryophyllinic acids were determined with cis-pinonic acid as surrogate. Also, the contribution of beta-caryophyllene oxidation products to aerosol organic carbon was evaluated. Aldehydes could not be analysed in real samples due to the insufficient extraction. The particle-into-liquid sampler proved to be suitable for the collection of aerosol particles for the elucidation of daily and diurnal variation of selected species. The optimized sample pretreatment, together with the analysis method, offer a promising approach for the study of aerosol chemical composition, where artifact formation is minimal and time resolution is good.
在 2007 年 8 月中旬于芬兰 SMEARII 站使用粒子进液体采样器采集大气气溶胶颗粒，并对其进行生物源酸分析。对包括阴离子交换和亲水-疏水平衡材料的固相萃取在内的样品预处理方法进行了优化。在 12.5 至 50ng/ml 的酸浓度范围内，从 10 和 20ml 样品中进行固相萃取的萃取效率约为 100%，平均相对标准偏差为 8.9%。醛的萃取效果较差，萃取效率为 69-163%，平均偏差为 10%。预处理后的样品通过反相高效液相色谱与离子阱质谱检测分析。采用所开发的分析程序，对于有机酸的检测限范围为 9-27μg/l 的提取样品，定量限为 31-90μg/l。臭氧氧化用于制备β-石竹烯酸（β-石竹烯酸），并在气溶胶样品中进行了研究。MS(2)实验用于确认顺式-蒎烯酸、顺式-和反式-蒎酮酸以及β-石竹烯酸的鉴定。使用真实标准品对样品中的庚酸、十六烷酸、顺式-蒎酮酸和反式-和顺式-蒎酮酸进行定量，而顺式-蒎酮酸则被用作替代物来确定反式-蒎酮酸和β-石竹烯酸的浓度。此外，还评估了β-石竹烯氧化产物对气溶胶有机碳的贡献。由于萃取不足，醛无法在实际样品中进行分析。粒子进液体采样器被证明适合收集气溶胶颗粒，以阐明选定物种的日变化和日变化。经过优化的样品预处理与分析方法相结合，为研究气溶胶化学成分提供了一种很有前途的方法，这种方法可最大限度地减少人为产物的形成，同时具有良好的时间分辨率。
