An electrospray/inductively coupled plasma dual-source time-of-flight mass spectrometer for rapid metallomic and speciation analysis: instrument design
A time-of-flight mass spectrometer (TOFMS), which employs inductively coupled plasma (ICP) and electrospray ionization (ESI) sources simultaneously, has been designed, constructed, and evaluated for comprehensive elemental speciation analysis. The simultaneous operation of both sources with a single mass spectrometer is an improvement over existing techniques. The mass analyzer shares a third-stage vacuum system, extraction region, acceleration region, field-free region, and two-stage reflectron between both sources. Most of the other components, such as first and second-stage vacuum systems, pre-extraction ion optics, microchannel plate detectors, and data acquisition are independent, to provide the greatest degree of flexibility in source operation and signal optimization. A detailed description is given of the design and optimization of the orthogonal acceleration and spontaneous drift geometry, energy discrimination, and the reflectron and preliminary performance data are presented.