Cobalt oxide（CoOorCo₃OIn elemental analysis experiments, especially in classical organic element analysis (such as the determination of carbon, hydrogen, nitrogen, sulfur, halogens, etc.), it mainly plays the role of catalyst and oxidant, and its role is crucial, especially in the determination of certain specific elements. Here are its specific functions:

1. Promote the combustion of organic matter/Oxidation:

In high-temperature combustion tubes (usually500-600°CCobalt oxide, as an efficient catalyst, can significantly accelerate the decomposition and oxidation process of organic samples in oxygen flow, especially in areas with higher temperatures.

It helps to decompose complex organic molecules and remove carbon from them（C）Convert to carbon dioxide（CO₂), hydrogen（H）Convert to water（H₂O）, sulfur（S）Convert to sulfur dioxide（SO₂) or sulfur trioxide（SO∝), halogen（Cl, Br, I）Convert to hydrogen halide（HCl, HBr, HI）, nitrogen（N）Convert to nitrogen gas according to different methods（N₂) or nitrogen oxides（NOₓ）。

This conversion is the basis for subsequent quantitative determination of elements, such as through infrared detectorsCO₂H₂O, or measured by titration, conductivity, or chromatographySTheNHalogens, etc.). Without efficient catalysts, combustion may not occur, resulting in by-products or elemental forms that do not meet detection requirements, leading to errors.

2. Special role in sulfur and halogen determination:

This is the most famous and critical application of cobalt oxide.

Decompose sulfur-containing gas interferents: During the combustion process, in addition to producing the target productSO₂, may also produce sulfur trioxide（SOEven trace amounts of sulfuric acid（H₂SO(₄). These substances may interfere or fail to react in subsequent detection steps, such as titration.

catalytic reductionSOAdsorption of halogens: Cobalt oxide can effectively catalyze sulfur trioxide（SOReduce to sulfur dioxide（SOThe latter is an easily and accurately detectable form in standard sulfur determination methods, such as titration. At the same time, it can also effectively adsorb or combine hydrogen halides produced by combustion（HCl, HBr, HI）To prevent them from evaporating or interfering with the determination of sulfur before reaching the sulfur detector.

Prevent sulfur loss and halogen interference: If there is no cobalt oxide (or other similar catalysts such as tungsten oxide)WO₃），SOIt may condense into sulfuric acid droplets in the colder part of the combustion tube, resulting in sulfur loss (lower result). If hydrogen halide is not adsorbed, it will directly enter the sulfur detection system (such as iodine titration cell), consume the titrant iodine, and cause significantly higher sulfur determination results (false positive).

Forming chromogenic compounds (auxiliary indicator): In the classic tubular combustion method, the reaction between hydrogen halide and cobalt oxide produces volatile blue or blue-green cobalt halides (such as...)CoCl₂ appears blue). This color change is sometimes used as a visual indication of whether combustion is complete and whether the halogen has been effectively fixed (especially in halogen determination).

3. As an oxidant:

Cobalt oxide itself contains oxygen, which can provide oxygen atoms at high temperatures to help oxidize non combustible intermediate products, such asCOEnsure that they are ultimately converted into (carbon particles, etc.)CO₂ andH₂OImprove combustion efficiency.

In summary, cobalt oxide plays a crucial role in elemental analysis, particularly inCHNS/OThe core role in halogen analysis is:

Ensure organic matter, fast combustion.

In sulfur determination: catalysisSOConvert to easily detectableSO₂, and adsorb hydrogen halides to prevent sulfur loss (bySOThe interference of condensation and halogens on sulfur determination (consumption of titrant).

In halogen determination: fixing halogens (forming cobalt halides) to prevent their volatilization loss, and can be assisted by color changes for judgment.

Note:

Cobalt oxide is usually filled in specific areas of the combustion tube in granular or linear form.

After long-term use, cobalt oxide will gradually become ineffective (reduced or saturated) and needs to be replaced regularly.

Due to the presence of cobalt (a heavy metal), the waste cobalt oxide after use needs to be disposed of in accordance with laboratory hazardous waste disposal regulations.

Modern elemental analyzers may use other catalyst systems, such as tungsten oxideWOHowever, cobalt oxide is present in sulfur due to its/The excellent performance in halogen determination is still widely used in many standards and classical methods.

Therefore, cobalt oxide is one of the key components to ensure the accuracy and reliability of elemental analysis results, especially for sulfur and halogens.

Tangshan Anfa Trading Co., Ltd. currently has stock supply:

SwitzerlandSANTIS， Cobalt oxide particles, cobalt trioxide particles, SA990700 25g/bottle

Cobalt (II,III)-oxide

Granulate | 0.025 kg

OEM item number

Costech 013010 / 011002

Elements 05 001 070

Eurovector E10105

Hekatech HE33854500

Perkinelmer 0240-1230

Thermo 338 22800