| In this dissertation the experimental and theoretical improvements for a hybrid mass analysis instrument--quadrupole ion trap/reflectron time-of-flight mass spectrometer (IT/reTOF)--have been described. This novel instrument combines the resolution, sensitivity, and selectivity of the quadrupole ion trap with the speed, high mass capability, and simplicity of the TOF. The resulting configuration is a mass detection device with high sensitivity and resolution for both continuous and static ionization techniques.;A flow probe has been used to directly introduce solutions of peptides into the IT/reTOF system for matrix-assisted laser-desorption ionization (MALDI). It is shown that this system can detect ions generated in liquid matrices in the continuous mode with pmole sensitivity. Quantitative results can be obtained with the presence of an internal standard.;The IT/reTOF has also been interfaced to electrospray ionization (ESI) to perform on-line tandem mass spectrometry for fast separation techniques such as capillary high performance liquid chromatography (capillary HPLC). The broadband excitation for isolating precursor ions is achieved by generating stored inverse Fourier transform waveform (SWIFT) in real time. Structural information of various peptides have been obtained with a high duty cycle.;Besides the efforts to perform on-line analysis, the IT/reTOF system has also been coupled to a static MALDI ionization source to detect DNA oligomers. It is found that by generating ions outside the ion trap, the fragmentation of the DNA ions has been reduced and intact molecular ions from 3 to 9 mers can be observed. Techniques such as bipolar pulsing and dynamic trapping have been used to improve the resolution and trapping efficiency.;A complete simulation of the external ion injection, cooling and extraction processes of the IT/reTOF system has been performed using the software SIMION 6.0. User programs have been developed to analyze the dynamic behavior of ions in the IT/reTOF device and a 3-D collision model is used to describe the ion-buffer gas molecule interactions. |
