Microwave-induced self-ignition: An efficient approach for high purity graphite digestion and multitechnique halogen...

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Graphite's chemical stability poses challenges for elemental analysis.
• Accurate determination of halogens in graphite is crucial for various applications.

Purpose of the Study:

• To develop and validate a single, efficient digestion method for high-purity graphite.
• To enable multitechnique determination of halogens (F, Cl, Br, I) in digested graphite samples.

Main Methods:

• Utilized microwave-induced self-ignition (MISI) in a closed, oxygen-pressurized system.
• Optimized conditions for digesting up to 600 mg graphite samples in quartz vessels.
• Employed diluted ammonium hydroxide solution for quantitative analyte absorption.

Main Results:

• Achieved >99% digestion efficiency for graphite samples.
• Validated accuracy better than 94% against pyrohydrolysis and certified reference materials.
• Demonstrated compatibility with ion chromatography (IC), ICP-mass spectrometry (ICP-MS), and ion-selective electrode (ISE) for halogen analysis.

Conclusions:

• MISI provides a rapid, effective, and interference-free digestion method for graphite.
• The technique eliminates the need for ignition aids, simplifying the process.
• Offers a powerful alternative for accurate halogen determination in challenging carbonaceous matrices.