Glow Discharge Mass Spectrometry (GD-MS)

Introduction of Glow Discharge Mass Spectrometry | GDMS

Glow Discharge Mass Spectrometry (GD-MS) is among the most potent solid-state analytical methods for directly determining solids’ traces, impurities, and depth profiling. Commercially available glow discharge mass spectrometers with fast and sensitive electrical ion detection enable the direct trace element determination of solid materials with good sensitivity and precision in the concentration range lower than ng g–1.6 

What is Glow Discharge Mass Spectrometry?

Researchers use Glow Discharge Mass Spectrometry to detect and quantify elements within solids, particularly metals and semiconductors. This susceptible method allows them to detect trace elements even in very small concentrations and analyze conductive and non-conductive materials with minimal sample preparation. As a result, they apply it extensively in areas such as metallurgy, electronics, and environmental analysis.

Scope of Glow Discharge Mass Spectrometry (GD-MS)

GD-MS, or Glow Discharge Mass Spectrometry, has several methods for analyzing and quantifying elements in a sample. The primary method involves using a high voltage to generate a glow discharge plasma over the sample in a low-pressure, inert gas environment, mostly argon. The energetic ions in the plasma sputter off the sample surface. Later, these atoms become further ionized inside the plasma. The ionized atoms enter a mass spectrometer, are separated by their mass-to-charge ratio, and are finally detected. 

Another essential technique in GD-MS is depth profiling, where researchers gradually sputter layers from a sample to analyze its composition relative to depth. This technique is very useful in studying layered materials, coatings, or diffusion processes within solids. These techniques make GD-MS a versatile tool for a wide range of applications in the analysis of metals, semiconductors, ceramics, and even biological samples.

How Does Glow Discharge Mass Spectrometry Work?

In Glow Discharge Mass Spectrometry (GD-MS), we usually generate argon plasma using a low current electrical discharge (milliamps) in a Glow Discharge Vacuum chamber filled with Argon gas. Positively charged Argon plasma ions then accelerate towards the cathode, which we form using the test sample in GDMS.

Due to bombardment by Argon plasma, researchers refer to the release of sample atoms at the cathode as ‘sputtering.’ Subsequently, the plasma ionizes the sputtered sample atoms, extracted through the anode into the mass spectrometer for detection and spectrometric analysis. Since individual compounds have their unique mass spectrum, operating the spectrometer in high-resolution mode provides a powerful technique for studying all trace and ultra-trace elemental constituents of inorganic materials.

Additionally, we can operate the Glow Discharge ion source in three different electrical modes: Direct Current (DC), Radio Frequency (RF), and pulsed Glow Discharge systems. We specifically use the radio frequency mode for non-conductive samples, whereas the pulsed mode produces higher energy plasma ions for sputtering and offers more analytical sensitivity.

GDMS has found widespread applications in analyzing trace-level elements and chemical species at surfaces and within conducting and nonconducting solids or dispersed liquids. Researchers also use it in nuclear technology to characterize atomic fuels and test materials for elemental and isotopic composition.

Pros and Cons of Glow Discharge Mass Spectrometry (GD-MS)

GDMS Test Conclusion

The GD-based techniques are of great use in bulk and depth profiling measurements for conductive and non-conductive samples, which have unrivaled application flexibility. One of the critical features of GD-MS is that the fast flow glow discharge mass spectrometry source uniquely offers high sensitivity with low interference levels. Moreover, a fast-flow glow discharge mass spectrometry source enables fast pumping and sample acquisition times, significantly enhancing sample throughput and laboratory productivity. GDMS has mainly been used in the characterization of nuclear concern samples. The “non-destructive” nature and fast sample preparation make the technique attractive for characterizing radioactive samples.

FAQs on Glow Discharge Mass Spectrometry | GDMS