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Ion-to-photon detectors may also detect ions with a mass of up to around 20,000 Da, better than microchannel plates. However, the resolution of the mass spectrum from an IPD equipped spectrometer is slightly lower. The noise in the spectrum, which may come from unfocused, slow speed ions, is also slightly higher.
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
A microchannel plate within a Finnigan MAT 900 sector mass spectrometer position-and-time-resolved-ion-counting (PATRIC) scanning array detector. An external voltage divider is used to apply 100 volts to the acceleration optics (for electron detection), each MCP, the gap between the MCPs, the backside of the last MCP, and the collector .
The mass spectrometer is fitted with a special device, a sniffer probe, that allows it to sample air (and tracer gas when confronted with a leak) at atmospheric pressure and to bring it into the mass spectrometer. This mode of operation is frequently used to locate a leak that has been detected by other methods, in order to allow for parts repair.
The scattered light proceeds to a photodiode which converts it to a signal, which is proportional to the mass of the analyte particles. This is why it is considered as a sort of "universal detector" [6] as it is able to detect all compound which are less volatile than the mobile phase, i.e. non volatile and semi-volatile compounds.
Trifluoroacetic acid (TFA) as additive to the mobile phase is widely used for complex mixtures of biomedical samples, mostly peptides and proteins, using mostly UV based detectors. They are rarely used in mass spectrometry methods, due to residues it can leave in the detector and solvent delivery system, which interfere with the analysis and ...
A chromatography detector is a device that detects and quantifies separated compounds as they elute from the chromatographic column.These detectors are integral to various chromatographic techniques, such as gas chromatography, [1] liquid chromatography, and high-performance liquid chromatography, [2] and supercritical fluid chromatography [3] among others.
Selected reaction monitoring (SRM), also called multiple reaction monitoring (MRM), is a method used in tandem mass spectrometry in which an ion of a particular mass is selected in the first stage of a tandem mass spectrometer and an ion product of a fragmentation reaction of the precursor ions is selected in the second mass spectrometer stage ...