Research And Application Of New Matrix Of MALDI-TOF MS Based On Graphene Materials

In recent years, Matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF MS） has been widely used in biological science, organic chemistry, analytical chemistry and medical science. As a soft-ionized technology, it has advantages such as salt tolerance, simple operation, quick analysis, signals easier to read than other MS techniques. In the MALDI process, matrix absorbs the laser radiation and transmits the energy to analytes, so the results are depended largely on the choice of matrix. The conventional MALDI MS matrix is often used to detect biological molecular. For the small molecular, the conventional matrix will generate a large number of background interference peaks, which discourage the application of MALDI MS in small molecular detection.Graphene is a novel carbon material, which has huge surface area, superior physical properties, chemical properties and good photoelectric properties. For this reason, graphene and graphene oxide have been used as the matrix in MALDI MS analysis. However, as a carbon material, it is too easy aggregation to get a stable and uniform signal peak. During the measuring procedure, it is easy to break away from the target plate and causing ion source pollution. In this article, for the first time, a soluble nanographene HBCCs was used as a MALDI MS matrix. The small molecule MALDI analysis method was established. This method not only overcame ion source pollution, also improved the stability of the signal and analytic precision. On the other hand, the magnetic graphene oxide/SiO₂ composites was prepared and used for the determination of quinolones drugs. The sample pretreatment separated by a magnetic field, which save time and labor.This thesis mainly contains four parts:1.Review:Introduce the development, application, actuality and existing problems of MALDI-TOF MS technology; theproperties of nanographeneorganic material are reviewed.2. The research of HBCCs as a novel MALDI-TOF MS matrix:The nanographene material HBCCs was used as a new MALDI matrix for determination of amino acids, antibacterial, anti HIV drugs and aromatic environmental contaminants. The reproducibility, stability and the matrix property of HBCCs were studied. Compared with conventional matrix, the HBCCs has better resolution and S/N. Compared with graphene, HBCCs has better reproducibility and stability. In addition, using HBCCs as matrix, the TFV, FTC in human blood and the uric acid in urine were detection by MALDI-TOF MS. This research developed a new matrix for small molecular MALDI MS analysis, which not only have excellent photoelectric absorption property and transmission property like graphene, but also overcome the disadvantages of carbon materials, and extend the application of MALDI MS.3. Preparation and characterization of magnetic graphene oxide/SiO₂ composites:The grapheneoxide was prepared by the modified Hummers. The Fe₃O₄@GO was prepared by a redox reaction using Fe²⁺ and GO in alkaline conditions. Using the TEOS as a slilyl reagent, prepared the MGO/SiO₂ by in situ hydrolysis method. The MGO/SiO₂ was characterized by FTIR and TEM, and the result shows that the MGO/SiO₂ has been successfully prepared.4. The MGO/SiO₂ composites for rapid detection of quinolones drugs: Ciprofloxacin, norfloxacin and ofloxacin were chosen as molecule models of quinolones drugs. Using the MGO/SiO₂ composites for rapid detection of quinolones drugs in real samples. The result shows that, MGO/SiO₂ not only has the ability to absorb the quinolones drugs, but also can be can be directly detected the ciprofloxacin, norfloxacin and ofloxacin in real samples by MALDI-TOF MS.