仪器气体分析

Instrumental Gas Analysis (IGA) measures gas-forming elements (C, H, O, N, and S) in solid materials, from ppm to percentage levels. A high-temperature furnace is used to rapidly heat the sample, converting certain elements into volatile forms for separation, detection, and measurement.

During instrumental gas analysis, carbon and sulfur are measured based on combustion and infrared detection. The analytical method involves complete oxidation of the solid sample through combustion in an oxygen plasma (above 2000°C). The sample is placed in a ceramic crucible within a high-frequency induction furnace, where it is heated. The combustion of the sample releases various gases, which are measured by four infrared detectors. Analysis of SO₂ determines sulfur content, while CO and CO₂ analysis determines carbon content.

Nitrogen, oxygen, and hydrogen are measured using inert gas fusion or solid carrier gas thermal extraction methods. The sample is placed in a graphite crucible, inserted into the furnace, and held between electrodes. After purging with an inert gas (He or Ar), a high current is passed through the crucible, raising the temperature (above 2500°C). Any gases produced in the furnace (CO, CO₂, N₂, and H₂) are released into a flowing inert gas stream and directed to the appropriate detector: infrared for O (measured as CO and CO₂) or thermal conductivity for N and H. The instrument is calibrated using certified reference materials covering the concentration range of the analyzed material.

Ideal Applications of IGA

• Determination of H, C, S, N, and O in solids, powders, or granular materials

• Partial gas analysis to quantify H, O, and N in various chemical bonding states and environments

• Differentiation between surface and bulk concentrations of H, O, and N

Our Strengths

• Precise determination of gas-forming elements from ppm to wt%

• Temperature programs and reactive gases can provide environmental information (surface vs. bulk) for H and O

Limitations

• Requires relatively large sample amounts (10 mg to gram range)

IGA Technical Specifications

• Detected signals: Infrared absorption and/or thermal conductivity

• Elements detected: H, C, N, O, and S

• Detection limit: ppm

• Depth resolution: Bulk technique (no spatial resolution)