Mass Spectrometry Method

What are the official methods of moisture content determination?

Moisture content determination is a crucial step in various industries, including food, pharmaceuticals, and materials science. Accurate measurement of moisture content helps ensure product quality, stability, and safety. Over the years, several official methods have been developed and standardized to determine moisture content accurately. These methods vary in their principles, accuracy, and applicability to different materials. Two commonly employed official methods are thermogravimetric analysis (TGA) and mass spectrometry (MS).

Thermogravimetric Analysis (TGA)

TGA is a widely used technique for determining moisture content by measuring the weight loss of a sample as it is heated. The sample is placed in a controlled environment within a furnace, and the temperature is gradually increased. As the sample loses moisture, its weight decreases, which is recorded by a highly sensitive balance. TGA provides accurate moisture content determination and can be used for a wide range of materials.

Mass Spectrometry (MS)

MS is an analytical technique that identifies and quantifies molecules based on their mass-to-charge ratio. In moisture content determination, MS techniques such as quadrupole mass spectrometry (QMS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) are commonly used. MS involves vaporizing the sample and ionizing the vaporized molecules. The ionized molecules are then separated based on their mass-to-charge ratio, and the abundance of each ion is measured. By analyzing the mass spectra, the moisture content of the sample can be determined. MS offers high sensitivity and specificity, making it suitable for trace moisture analysis.

Comparison of TGA and MS

The choice between TGA and MS for moisture content determination depends on the specific requirements of the application. TGA is generally more straightforward and less expensive than MS. It is particularly suitable for materials that can withstand high temperatures without significant decomposition. MS, on the other hand, is more sensitive and can provide additional information about the sample's composition. It is often used for trace moisture analysis or when the sample is sensitive to high temperatures.