Rapid determination of small molecule pollutants using metal-organic frameworks as adsorbent and matrix of MALDI-TOF-MS
Rapid determination of small molecule pollutants using metal-organic frameworks as adsorbent and matrix of MALDI-TOF-MS
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以金属有机框架为吸附剂和MALDI-TOF-MS基质快速测定小分子污染物
DOI：
10.1016/j.micromeso.2016.10.032
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发表时间：
2017
影响因子：
5.2
通讯作者：
Cai Yaqi
中科院分区：
文献类型：
--
作者：
Wang Saihua;Niu Hongyun;Zeng Tao;Zhang Xiaole;Cao Dong;Cai Yaqi
基质辅助激光解吸电离飞行时间质谱仪(MALDI-TOF-MS)具有灵敏度高、操作简便等优点，已被广泛应用于大分子物质的分析。然而，由于低质量区的基质干扰，直接用MALDI-TOF-MS分析小分子仍然是一个挑战。本文成功地将金属有机骨架(MOF-5、MOF-235、铜-BTC-MOF和UIO-66(Zr)-2OH)用作MALDI-TOF-MS分析小分子污染物的吸附剂和有效基质。以苯并(A)芘(BaP)和全氟化合物(PFCs)为模型分析对象，分别在正反射模式和负反射模式下用LDI法研究了MOF的基质函数。结果表明，MOF具有很高的激光解吸/电离效率，并且在正离子和负离子模式下都能很好地发挥作用。与常规基质的MS光谱相比，在MOFS基质上获得的MS光谱只有去质子化的分子离子峰，没有背景干扰。此外，MOF具有较大的比表面积和π-π堆积结构，还可以高效、快速地从溶液中富集痕量小分子污染物。基于此，我们建立了MOFS-固相萃取(SPE)-MALDI-TOF-MS相结合的简便方法，实现了对实际水样中全氟辛烷磺酸(PFOS)的直接分析。
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been commonly used for the determination of macromolecules owing to the high sensitivity and convenience. However, the direct analysis of small molecule with MALDI-TOF-MS remains a challenge due to the matrix interference in the low mass region. In this paper, metal-organic frameworks (MOFs: MOF-5, MOF-235, Cu-btc MOFs and Uio-66(Zr)-2OH) were successfully used as both adsorbent and significant matrix of MALDI-TOF-MS method for the analysis of small molecule pollutants. Benzo(a)pyrene (BaP) and perfluorinated compounds (PFCs) were chosen as model analytes to investigate the matrix function of MOFs with LDI measurement in positive and negative reflection mode, respectively. As a result, MOFs exhibit high laser desorption/ionization efficiency and function well in both positive-ion and negative-ion modes. Compared to the MS spectra with conventional matrices, MS spectra obtained on MOFs matrix are only featured by deprotonated molecule ion peaks without background interference. Furthermore, MOFs, with large surface area and π-π stacking structure, can also enrich trace amounts of small molecule pollutants from solution efficiently and quickly. According to these, we developed a simple method in which MOFs-solid-phase extraction (SPE) enrichment was combined with MALDI-TOF-MS to realize the direct analysis of perfluorooctanesulfonate (PFOS) in real water samples.