In mass spectrometry (MS), the detector plays a crucial role as the final component of the instrument. Its main function is to detect and measure the ions that have been separated based on their mass-to-charge ratio (m/z) in the mass analyzer. Here’s a breakdown:
- Detection of ions: After ions are generated in the ion source and separated in the mass analyzer, they reach the detector. The detector senses these ions and converts their impact into an electrical signal.
- Signal generation: Each ion hitting the detector produces a small current or pulse. The strength of this signal is proportional to the number of ions hitting the detector, which provides quantitative information.
- Data output: The electrical signals from the detector are sent to a computer, which generates a mass spectrum. This spectrum shows the intensity of ions versus their mass-to-charge ratio (m/z), allowing identification and quantification of the compounds in the sample.
- Types of detectors: Common detectors in MS include:
- Electron multiplier – amplifies ion signals.
- Faraday cup – measures ion current directly.
- Microchannel plate – detects ions with high sensitivity.
- Time-of-flight (TOF) detectors – record ions based on their arrival time.
In short: The detector in mass spectrometry “sees” the ions and converts their presence into measurable signals, which are used to generate the mass spectrum for analysis.