Abstract
A laser desorption time-of-flight (TOF) mass spectrometer has been developed in order to analyze non-volatile, thermally labile and high mass organic compounds, in which the “gradient electric field type ion reflector” was used for time focusing. Higher detection sensitivity for high mass ions was achieved by adding a blind type ion-electron converter to the micro-channel plate (MCP) ion detector. Two TOF spectrum measurement systems were constructed, with which two measurement methods called as “AD method” and “TDC method” were able to be selected to obtain the spectrum sensitively and accurately in a short time.
For sample preparation, “metal fine powder and glycerol matrix” method was confirmed to be very effective to increase the yield of high mass molecular ions.
This mass spectrometer was successfully applied to the detection of quasi-molecular ions from many high mass organic compounds, such as Cytochrome-C (mol. wt. 12,384), Bovine Trypsin (mol. wt. ~24,000) and Carboxypeptidase-A (mol. wt. 34,472).
