Enhanced Laser Desorption Ionization Based On Ordered Microstructure Materials

Mass spectrometry is a significant analytical technique for the analysis of material composition and has widely applied in molecular identification,biological tissue composition analysis,tissue slice imaging and so on.The generation of molecular ions,including desorption and ionization of sample,is a prerequisite in the substance detection for mass spectrometry.Among various desorption and ionization methods,surface assisted desorption ionization(SALDI)is one of the most prevalent ionization techniques,due to its significantly lower matrix interferences,high reproducibility and high salt tolerance.In a SALDI process,the desorption and ionization of the analyte highly depend on the photothermal conversion and heat transfer efficiencies of the substrates.Many studies have shown that the organization of nano building blocks significantly altered the dynamics of the interaction between light and nanomaterials.So,we used the photonic crystals with inverse opal structure as SALDI substrate to promote laser desorption and ionization.Here,we have prepared inverse opal photonic crystal by using strong ultraviolet-absorbing tungsten-titanium oxide and broadspectrum light-absorbing carbon materials as framework materials,respectively.By coupling the stop band edge of the photonic crystal and the laser wavelength,the interaction between the laser and the framework material was enhanced,which further enhanced the absorption and conversion of the laser energy.Then,we used the inverse opal photonic crystal as substrate for mass spectrometry detecyion and studied the enhancement of the slow light effect.And based on the high sensitivity of the photonic crystal substrate,it was used for the quantitative detection of biomarkers in serum.In this thesis the main contents are:(1)preparation and characterization of ordered microstructured materials: Based on the strong ultraviolet absorption of tungstentitanium oxide and the broad-spectrum light absorption property of carbon material,tungsten-titanium oxide inverse opal photonic crystal and carbon inverse opal photonic crystal were prepared.And the microstructure and optical properties of the materials were characterized and analyzed(Chapter 2).(2)ordered microstructured materials for mass spectrometry detection: The tungsten-titanium oxide inverse opal photonic crystal and carbon inverse opal photonic crystal were used as the substrates for mass spectrometry detection.By coupling the band gap edge of the photonic crystal and the laser wavelength,the detection sensitivity of SALDI mass spectrometry was enhanced.In addition,by changing the wavelength of the detection laser,the universality of the slow light effect for enhancing laser desorption and ionization was verified.And we also studied the slow light bandwidth of the carbon inverse opal photonic crystal(Chapter 3).(3)quantification of CUMS biomarkers by using mass spectrometry: The chronic unpredictable mild stress(CUMS)biomarkers in serum were detected by using tungsten-titanium oxide inverse opal photonic crystal as enhanced substrate.we coupled internal standard quantification to quantify the biomarkers.The control group and the model group were set up to analyze the influences of CUMS on the biological metabolism(Chapter 4).