Department of Analytical Chemistry, Nutrition and Food Science, IIAA-Institute for Food Analysis and Research, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Anal Chim Acta. 2012 Aug 31;740:50-7. doi: 10.1016/j.aca.2012.06.027. Epub 2012 Jun 26.
A method for the determination of seven perfluorinated carboxylic acids and perfluorooctane sulphonate (PFOS) in aqueous samples using low-cost polymeric sorptive extraction as sample preparation technique, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination has been developed and validated. Simplicity of the analytical procedure, low volume of solvent and sample required, low global price and a good selectivity providing cleaner extracts are the main advantages of this extraction technique. Polydimethylsiloxane (PDMS) and polyethersulfone (PES) materials were evaluated and compared to achieve the best extraction efficiencies. Hence, different variables have been optimized, viz.: sample pH, concentration of an ion-pairing agent (tetrabutylammonium), ionic strength, sample volume, extraction time, desorption solvent volume, desorption time and the need for auxiliary desorption techniques (sonication). Overall, PES leaded to a better sensitivity than PDMS, particularly for the most polar compounds, reaching detection limits (LODs) in the 0.2-20 ng L(-1) range. The precision of the method, expressed as relative standard deviation (RSD), was lower than 16%. Finally, the PES material was employed for the analysis of sea, sewage and fresh water samples. Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were detected in all the analyzed influent samples reaching levels of up to 401 ng L(-1). In surface water, perfluorohexanoic acid (PFHxA) exhibited the highest concentrations, up to 137 ng L(-1).
一种使用低成本聚合物吸附萃取作为样品制备技术，结合液相色谱-串联质谱（LC-MS/MS）测定法，测定水样中七种全氟羧酸和全氟辛烷磺酸（PFOS）的方法已经开发并得到验证。该萃取技术的主要优点是分析程序简单、所需溶剂和样品量少、全球价格低廉、选择性好，可提供更清洁的提取物。评估并比较了聚二甲基硅氧烷（PDMS）和聚醚砜（PES）材料，以实现最佳的萃取效率。因此，优化了不同的变量，即：样品 pH 值、离子对试剂（四丁基铵）的浓度、离子强度、样品体积、萃取时间、洗脱溶剂体积、洗脱时间以及是否需要辅助洗脱技术（超声处理）。总体而言，PES 比 PDMS 具有更好的灵敏度，特别是对于最极性的化合物，检测限（LOD）在 0.2-20ng/L 范围内。该方法的精密度（以相对标准偏差（RSD）表示）低于 16%。最后，PES 材料用于海水、污水和淡水样品的分析。在所有分析的进水样本中均检测到全氟庚酸（PFHpA）、全氟辛酸（PFOA）、全氟壬酸（PFNA）和全氟癸酸（PFDA），浓度高达 401ng/L。在地表水中，全氟己酸（PFHxA）的浓度最高，达到 137ng/L。
