The Flame Ionization Detector (FID) is a widely used detector in gas chromatography. It is particularly valued for its sensitivity to organic compounds, making it a key tool in many analytical applications involving hydrocarbons and other volatile organic compounds.
Detection of Organic and Volatile organic compounds:
The FID is highly sensitive to organic molecules that contain carbon atoms. It is capable of detecting even trace amounts of these substances, making it highly effective for analyzing a wide variety of volatile organic compounds (VOCs).
Chemical Ionization of Analytes:
The primary function of the FID is to detect substances by ionizing them. In the FID, the eluent from the gas chromatograph's column is directed into a hydrogen flame. The organic compounds in the eluent are burned in this flame, which contains an excess of hydrogen and a limited amount of oxygen.
Production of Ions and Electrons in the flame:
When organic compounds are burned in the flame, they produce ions and electrons. This ionization process happens as the carbon atoms in the compound are oxidized to carbon ions (C+) and electrons are released.
Generation of Current during analysis:
The ions produced in the flame are collected on a polarized electrode, creating an electrical current. The strength of this current is proportional to the amount of ionized carbon in the flame, which in turn is related to the concentration of organic compounds in the sample.
Quantitative Analysis of the Residual solvents:
The current generated by the ions is measured and used to create a signal. This signal is proportional to the concentration of the organic compounds in the sample, allowing for both qualitative and quantitative analysis. The greater the concentration of the compound, the larger the signal produced.
Wide Linear Response:
The FID is known for its wide linear response, meaning it can accurately measure a wide range of concentrations of organic compounds. This makes it very versatile and useful in both environmental monitoring and in industries such as pharmaceuticals and petrochemicals.
Advantages of FID:
- High Sensitivity: Particularly to carbon-containing molecules.
- Wide Linear Range: Effective across a broad range of concentrations.
- Robustness and Reliability: Handles complex samples well and is generally low-maintenance.
Applications:
- Environmental Analysis: Monitoring air and water for pollutants.
- Petrochemical Industry: Analyzing hydrocarbons and fuels.
- Pharmaceuticals: Quality control and purity testing of Raw materials, finished goods and in-process samples, predominantly the organic volatile compounds and residual solvents analysis.
- Food and Flavor Industry: Analyzing flavor compounds and contaminants.
In summary, the Flame Ionization Detector is a cornerstone technology in gas chromatography, primarily valued for its ability to detect and quantify low concentrations of organic compounds with high precision and reliability.
Read also:
- Potentiometric Titration in Pharmaceutical Analysis
- Karl Fischer Titration in Pharmaceutical Analysis
Resource Person: MD. AL-AMIN
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