Magnetic metal-organic framework nanocomposites for enrichment and direct detection of environmental pollutants by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Zhijian Li; Qianjing Liu; Xiaohui Lu; Chunhui Deng; Nianrong Sun; Xin Yang

doi:10.1016/j.talanta.2018.10.058

Magnetic metal-organic framework nanocomposites for enrichment and direct detection of environmental pollutants by negative-ion matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Talanta. 2019 Mar 1:194:329-335. doi: 10.1016/j.talanta.2018.10.058. Epub 2018 Oct 18.

Authors

Zhijian Li¹, Qianjing Liu², Xiaohui Lu¹, Chunhui Deng³, Nianrong Sun², Xin Yang⁴

Affiliations

¹ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
² Department of Chemistry, The Fifth People's Hospital of Shanghai, Institutes of Biomedical Sciences, and Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200433, China.
³ Department of Chemistry, The Fifth People's Hospital of Shanghai, Institutes of Biomedical Sciences, and Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200433, China. Electronic address: chdeng@fudan.edu.cn.
⁴ Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China. Electronic address: yangxin@fudan.edu.cn.

PMID: 30609539
DOI: 10.1016/j.talanta.2018.10.058

Abstract

Nowadays, the detection and removal of environmental pollutants are particularly important, owing to their harmful influence on human beings' health. Specifically, metal-organic frameworks (MOFs) as the hot materials with great potential have been widely employed as adsorbents for pollutants removal, as well as matrixes for mass spectrometry detection. In this work, magnetic Zr-based MOF (denoted as Fe₃O₄@PDA@ZrMOF) with outstanding properties, such as low background interference, high desorption/ionization efficiency, excellent signal reproducibility, ultrahigh surface area and strong magnetic responsiveness, was synthesized by a modified thermal annealing method. The Fe₃O₄@PDA@ZrMOF not only can be utilized as adsorbent towards small molecules by π-π stacking interaction between nitrophenols and ZrMOF, but also can serve as a matrix for detection of small molecules under the negative ion mode of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). As a result, with the use of Fe₃O₄@PDA@ZrMOF, the detection limits of 4-nitrocatechol and 4-nitroguaiacol were estimated to be about 68 μg/ml and 25 μg/ml, respectively. In addition, enrichment of nitrophenols from PM_2.5 was investigated. The detected mass concentrations of 4-nitrocatechol and 4-nitroguaiacol in collected PM_2.5 samples were 0.11 ng/m³ and 0.15 ng/m³, respectively, indicating the highly efficient enrichment performance of Fe₃O₄@PDA@ZrMOF for low-abundance nitrophenol compounds in the environment.

Keywords: Adsorbent; Environmental pollutant; MALDI-TOF MS; Matrix; Metal organic frame.