State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, P.O. Box 2871, 18 Shuangqing Road, Haidian District, Beijing 100085, China.
Talanta. 2011 Jul 15;85(1):345-52. doi: 10.1016/j.talanta.2011.03.062. Epub 2011 Apr 5.
Determination of perfluorinated compounds (PFCs) is very important because of their potential hazards to the environment and human health. In present work, 1,8-bis (tetramethylguanidino)-naphthalene (TMGN), a superbasic proton sponge, was firstly employed as the matrix for quantitative detection of acidic PFCs in environmental water samples by Matrix-assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF-MS). Several acidic PFCs, such as perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA), were selected as model analytes for demonstrating the feasibility of the detection method. The results showed that deprotonated ions of these PFCs were detected without any other matrix ions interference. The achieved sensitivity with TMGN for PFOS detection was ten-fold higher than that with 1,8-bis (dimethyl-amino)-naphthalene (DMAN) which was used for the detection of fatty acid by MALDI-TOF-MS. The high sensitivity of this method made it feasible to monitor and quantify acidic PFCs in complicated environmental water samples. Furthermore, a novel combined strategy of solid phase extraction (SPE) followed by MALDI-TOF-MS detection was developed for quantifying PFCs in environmental water samples. The calibration curves with a wide linear dynamic range (0.1-10 ng L(-1) for PFOS, PFHxS, and PFBS, and 0.5-50 ng L(-1) for PFOA, PFNA, and PFDA.) were obtained. The limit of detection (LOD) for PFOS of this method was 0.015 ng L(-1) (a signal-to-noise ratio of 3), which was lower than the LOD (0.036 ng L(-1)) obtained by high-pressure liquid chromatography/tandem mass spectrometry (LC-MS/MS) method. Moreover, the strategy was used to detect the selected PFCs in water samples collected from Xiaoqinghe river and Gaobeidian wastewater. The achieved concentrations of PFCs were closed to those obtained by LC-MS/MS method. It is indicated that the proposed MALDI-TOF-MS method with TMGN as the matrix is much reliable and can be used as an alternative method to detect trace PFCs in environmental water samples.
全氟化合物 (PFCs) 的测定非常重要，因为它们对环境和人类健康具有潜在危害。在本工作中，首次将超碱性质子海绵 1,8-双(四甲基胍基)-萘 (TMGN) 用作环境水样中酸性 PFCs 的定量检测基质，通过基质辅助激光解吸/离子化-飞行时间质谱 (MALDI-TOF-MS)。选择全氟辛烷磺酸 (PFOS) 和全氟辛酸 (PFOA) 等几种酸性 PFCs 作为模型分析物，以证明检测方法的可行性。结果表明，这些 PFCs 的去质子离子在没有任何其他基质离子干扰的情况下被检测到。与用于 MALDI-TOF-MS 检测脂肪酸的 1,8-双(二甲基氨基)-萘 (DMAN) 相比，TMGN 对 PFOS 的检测灵敏度提高了十倍。该方法的高灵敏度使得在复杂的环境水样中监测和定量酸性 PFCs 成为可能。此外，还开发了一种固相萃取 (SPE) 与 MALDI-TOF-MS 检测相结合的新策略，用于定量环境水样中的 PFCs。获得了宽线性动态范围 (0.1-10 ng L(-1) 用于 PFOS、PFHxS 和 PFBS，0.5-50 ng L(-1) 用于 PFOA、PFNA 和 PFDA) 的校准曲线。该方法对 PFOS 的检测限 (LOD) 为 0.015 ng L(-1) (信噪比为 3)，低于高效液相色谱/串联质谱法 (LC-MS/MS) 方法获得的 LOD (0.036 ng L(-1))。此外，该策略还用于检测从小清河和高碑店污水中采集的水样中选定的 PFCs。获得的 PFCs 浓度与 LC-MS/MS 方法获得的浓度接近。这表明，使用 TMGN 作为基质的 MALDI-TOF-MS 方法非常可靠，可以作为检测环境水样中痕量 PFCs 的替代方法。
