Real-Time Distinguishing of the Xylene Isomers Using Photoionisation and Dissociation Mass Spectra Obtained by Femtosecond Laser Mass Spectrometry (FLMS)
Multiphoton ionisation (MPI) dissociative ionisation of xylene isomers was investigated by means of the femtosecond (fs) laser mass spectrometry (FLMS) method using a custom-built linear time of flight (TOF) mass spectrometer. (Information about TOF-MS system: https://doi.org/10.1016/j.ijms.2009.12.014)
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Experimental process: - A custom-designed and built time-of-flight (TOF) mass spectrometer was used. - The spectra are recorded around 1.5x10^-6 mbar pressure which was maintained as constant as possible. - The Background pressure was kept around 10^-8 mbar before the sample introduction. - A microchannel plate (MCP) detector (El-Mul Technologies LTD., Israel) is used to detect the generated ions. - The recording and analyses of the mass spectra were performed using a custom-built MATLAB program. - The resolution of the mass spectrometer was determined to be m/Δm ≈ 200 at the mass of 100 amu. - Xylene isomers of a 99% purity were obtained from Alfa Aeser and used without further sample preparation. - The samples were introduced to vacuum chamber effusively via a manual leak valve (Mdc vacuum, ulv-150, CA, USA). Data formats: - In the MassSpectralDatabase folder laser pulse power and laser wavelength-dependent background adjusted mass spectra of the xylene isomers were presented. Files were named as [isomer]_[wavelength]_[power] for example oxylene_800nm_1000mW.csv is a csv (comma-separated file) containing ten mass spectra of the o-xylene isomers obtained by using 800 nm ionisation laser wavelength and 1000 mW laser pulse power. The first column is the time readings from oscilloscope (scale is microsecond). The remaining (2nd to 11th) columns are ion intensity readings from oscilloscope (scale is volt). - In the RealTimeSpectra folder laser pulse power-dependent, background adjusted raw mass spectra were shared as a csv format. The first column is the time readings from oscilloscope (scale is microsecond). The second column is ion intensity readings from oscilloscope (scale is volt).