Multiplexed inlet system

Miniature cylindrical ion trap array An approach to the rapid screening of large numbers of samples in the areas of proteomics, industrial process monitoring, and metabolomics is to use a multiplexed inlet system with a multiplexed mass spectrometer having an equal number of parallel sample channels. To this end, a high-throughput mini-CIT array mass spectrometer has been developed and tested. 

An application for multiplexed diode-laser sensors with a potentially large impact is for measurements of important parameters at several locations in a gas turbine combustion system. In this example, illustrated schematically in Fig. 24.1, the multiplexed diode lasers are applied for simultaneous absorption measurements in the inlet, combustion, afterburner, and exhaust regions. For example, measurements of O2 mass flux at the inlet may be determined at the inlet from Doppler-shifted O2 absorption lineshapes near 760 nm. Measurements of gas temperature and H2O concentrations in the combustion and afterburner regions may be determined from H2O lineshape measurements near 1.4 pm. Finally, measurements of velocity, temperature, and species concentrations (e.g., CO, CO2, unburned hydrocarbons) may be recorded in the exhaust for the determination of momentum flux (component of thrust) and combustor emissions. 

A similar mass spectrometric detection system is available commercially and is realized by a multiplexing electrospray inlet in combination with a time-of-flight (TOF) mass spectrometer that has a sufficiently high data acquisition rate. Like the above-described optical switch, the effluent of the HPLC channels is nebulized in individual probe tips and sprayed toward a rotating cylinder with a slit. By stepping this slit very rapidly from one probe tip to another, again a data acquisition rate of approximately one spectrum per channel can be reached in 1 second. Unlike the multiplex PDA detector, this multiplex mass spectrometric detector is normally connected to a HPLC system by a flow splitter. ... 

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