Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) is a powerful analytical technique used for precise mass measurement and structural characterization of complex molecules. It’s one of the official methods for determining moisture content in various substances.
**Principle**
FT-ICR MS operates on the principle of ion cyclotron resonance. When ionized molecules are trapped in a strong magnetic field, they rotate in circular orbits with a frequency proportional to their mass-to-charge ratio (m/z). By measuring the frequency of these oscillations via Fourier transform, the exact m/z values of the ions can be determined.
**Procedure**
In moisture content determination using FT-ICR MS, the sample is introduced into a heated chamber where the moisture evaporates. The vapor is then ionized using an electron impact or chemical ionization source. The resulting ions are trapped in a high-resolution FT-ICR cell, and their masses are accurately measured.
**Moisture Content Calculation**
The moisture content is calculated by comparing the signal intensities of water ions (H2O+ and H3O+) to the signal intensities of other ions present in the sample. The weight percentage of water is then determined based on the relative ion abundances.
**Advantages**
* **High Accuracy:** FT-ICR MS offers exceptional mass accuracy (<1 ppm), enabling precise measurement of moisture content. * **Wide Applicability:** This method can be used to measure moisture content in various materials, including food, pharmaceuticals, and chemical products. * **Structural Characterization:** In addition to moisture content determination, FT-ICR MS can provide valuable information on the structure and composition of the sample. **Summary** FT-ICR MS is a robust and reliable method for moisture content determination, offering high accuracy and broad applicability. Its unique ability to perform structural characterization makes it an invaluable tool for research and industry.