What are some detectors used in Gas Chromatography and how do they operate? What are the advantages and disadvantages of each detector compared to others?
Gas Chromatography uses detectors such as Flame Ionization Detector, Thermal Conductivity Detector, Electron Capture Detector, Photo Ionization Detector, and Mass Spectrometer. Each detector operates differently and has its own advantages and disadvantages.
Flame Ionization Detector (FID)
The FID operates by burning the sample and measuring the ions produced. Its advantage is its wide range of detectability, being able to detect a variety of compounds. However, the main disadvantage of FID is that it destroys the sample in the process.
Thermal Conductivity Detector (TCD)
TCD operates by measuring changes in thermal conductivity of the gas carrier. It is non-destructive and has a wide range of detectability. One disadvantage of TCD is that it is less sensitive than other detectors, which may result in lower detection limits.
Electron Capture Detector (ECD)
ECD operates by detecting the drop-in current caused when sample molecules capture electrons. It is highly sensitive to halogens, making it ideal for detecting compounds containing halogens. However, ECD is not suitable for compounds that do not contain electronegative elements.
Photo Ionization Detector (PID)
PID operates by ionizing the sample with UV light and measuring the resulting current. An advantage of PID is that it provides instant measurements, allowing for real-time analysis. However, PID is not as selective as other detectors, potentially leading to issues with compound identification.
Mass Spectrometer (MS)
MS operates by ionizing the sample and sorting the ions based on their mass to charge ratio. It provides highly detailed information about the components present in the sample. However, MS is more complex and expensive than other detectors, making it less accessible for some laboratories.
In conclusion, each detector used in Gas Chromatography offers unique advantages and disadvantages depending on the specific analytical needs. Understanding the operation and characteristics of each detector can help researchers choose the most suitable option for their analytical applications.