Metal Elements Research And Other Applications Of Microwave Plasma Torch Mass Spectrometry

Ambient mass spectrometry allows the in situ,real-time,rapid,nondestructive,online,high throughput,low sample consumption analysis be performed with no sample pretreatment.Consequently,direct ionization technology is of increasing intrest for detection of trace analytes in complex matrix.The application of ambient mass spectrometry has greatly improved and renders mass spectrometry method for practical samples possible.In this paper,the new method of microwave plasma torch ionization mass spectrometry(MPT-MS)is used to analyze the metal elements,to develop its application in other areas(such as environmental analysis,food safety,criminal investigation,etc.).This thesis included 5 chapters:1.Basic principle,opetating modes and typical instrumentation of ambient mass spectrometry ionization techniques have been reviewed.The important progresses in drugs analysis,Building stone analysis,food analysis,environment analysis and other fields have been systematically discussed.2.The new microwave plasma torch quadrupole mass spectrometry(MPT-Q-MS)was used as the research platform,testing the performance of the quadrupole mass spectrometer prototype.At the same time,the ionization mechanism of ion source was analyzed.On this basis,this paper developed a different injection method for the solid,liquid,gaseous samples.3.As microwave plasma torch(MPT)soft ionization,no Ar background characteristics,the comparative experiment was performed on the quadrupole mass spectrometer(Q-MS)and the linear ion trap mass spectrometer(LTQ-MS).According to the characteristics of Q-MS instruments,more than 20 kinds of metal elements were studied,and the preliminary rules were obtained.But the Q-MS instrument has no tandem mass spectrometry function,in order to better study the metal ions in water samples.Using LTQ-MS instruments,the mass spectrometric behavior of metal ions was analyzed by tandem mass spectrometry in the positive/negative ion mode.The research indicates that The limit of determination(LOD)of Q-MS instrument reached the same order of magnitude(ng·L-1)as the LTQ-MS instrument,and the mass spectra of metal elements on the Q-MS instrument are predominantly [M]+,[MOH]+,[MO]+,but the mass spectra of metal elements on the LTQ-MS instrument are predominantly [M(NO3)a(H2O)b](a-1)+.Moreover,in terms of quantitative analysis,the negative ion mode of the LTQ-MS instrument is better than the positive ion mode.4.In order to expandding the application of the microwave plasma torch(MPT),combined with high temperature thermal effect and ionization effect of the microwave plasma torch.A novel and simple mass spectrometric method based on microwave plasma torch(MPT)was developed to rapidly detect aflatoxin B1 on the rice,and evaluated the quality of a variety of commercially available rice,without sample pretreatment.Quantitative results showed that the limit of detection(LOD)by using MS2 procedure was estimated to be 0.12μg·L-1(ppb)for aflatoxin B1.However through the analysis of poison,the MPT-LTQ-MS method can provide a means for rapid qualitative analysis of criminal investigation.In this paper,the MPT mass spectrum of tetracycline was obtained and the quantitative analysis mainlywas based on the characteristic fragments of tetracycline.The detection of four kinds of commercially available honey is safe in the national standard allowable range.Therefore,this method provides a new method for mass spectrometry analysis of direct analysis of organic samples.5.In conclusion,the microwave plasma torch mass spectrometry have been summarized and expolred its developments trend in future.