combustion tube

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A combustion tube is a laboratory glassware used primarily in organic chemistry for conducting combustion reactions. It’s a straight, narrow tube made of heat-resistant glass, usually borosilicate glass, with one end sealed.

Here’s how it typically works:

  1. Preparation: The sample to be combusted is usually placed inside the combustion tube. This sample is often an organic compound or a mixture of compounds.
  2. Sealing: After loading the sample, the open end of the tube is sealed, often using a stopper or a glass rod. This ensures that the combustion reaction takes place within a closed system.
  3. Combustion: The sealed tube is then placed in a combustion furnace, which raises the temperature to a level where combustion of the sample occurs. This typically involves heating the sample in the presence of excess oxygen.
  4. Collection of Products: As the sample combusts, it reacts with oxygen to produce carbon dioxide and water vapor, along with other possible products depending on the composition of the sample. These products are collected and can be analyzed using various techniques such as gas chromatography.
  5. Analysis: The collected products can provide valuable information about the composition of the original sample. For example, the amount of carbon dioxide produced can be used to determine the carbon content of the sample, which is useful in determining its molecular formula or identifying functional groups present in organic molecules.


Combustion tube

  1. Elemental Analysis: Combustion tubes are commonly used to determine the elemental composition of organic compounds. By combusting a sample in the presence of excess oxygen, the carbon and hydrogen in the sample are converted to carbon dioxide and water vapor, respectively. The amounts of carbon dioxide and water produced can then be measured, allowing calculation of the carbon and hydrogen content of the sample. This information is crucial for determining the empirical formula of the compound.
  2. Identification of Functional Groups: The combustion of organic compounds in a combustion tube can provide information about the functional groups present in the molecule. For example, the presence of nitrogen-containing functional groups (such as amines or amides) can be detected by analyzing the nitrogen-containing combustion products (such as nitrogen oxides). Similarly, sulfur-containing functional groups can be detected by analyzing sulfur dioxide produced during combustion.
  3. Calorimetry: Combustion tubes are also used in calorimetry experiments to measure the heat released during combustion reactions. By knowing the heat released and the mass of the sample, it’s possible to calculate the heat of combustion per unit mass, which can provide valuable information about the energy content of the compound.
  4. Isotope Ratio Mass Spectrometry (IRMS): In some cases, combustion tubes are used as part of sample preparation for isotope ratio mass spectrometry. By combusting samples containing isotopically labeled atoms (such as carbon-13 or nitrogen-15), researchers can analyze the isotopic composition of organic compounds, which can be useful in fields such as environmental science, geochemistry, and food authenticity testing.
  5. Quantitative Analysis: Combustion tubes can be used for quantitative analysis of organic compounds. By carefully controlling the conditions of combustion and analyzing the products, it’s possible to determine the concentration or mass of specific components in a sample.
SKU: ACS67956CHEM0 Category:
  1. Material: Combustion tubes are typically made of high-quality borosilicate glass, which is resistant to heat and chemical corrosion. Borosilicate glass can withstand the high temperatures required for combustion reactions and is compatible with most organic solvents and reagents.
  2. Dimensions: Combustion tubes are usually long, straight tubes with a narrow diameter to maximize the surface area-to-volume ratio and ensure efficient combustion. The length and diameter of the tube can vary depending on the sample size and the desired combustion conditions. Common lengths range from 15 cm to 60 cm, and diameters typically range from 6 mm to 25 mm.
  3. Sealing: One end of the combustion tube is sealed to contain the sample and combustion products during the reaction. The sealing can be achieved using a glass stopper, a ground glass joint, or a glass rod fused to the end of the tube. The sealing method should ensure a tight seal to prevent the escape of gases during combustion.
  4. Uniformity: The combustion tube should be uniform in diameter and thickness along its entire length to ensure consistent heating and combustion of the sample. Variations in diameter or thickness can lead to uneven heating and inaccurate results.
  5. Heat Resistance: The combustion tube should be able to withstand high temperatures without cracking or deforming. Borosilicate glass has excellent heat resistance and is suitable for use in combustion reactions conducted at temperatures up to several hundred degrees Celsius.
  6. Compatibility: The combustion tube should be compatible with the combustion furnace or apparatus used for heating the sample. It should fit securely into the furnace without excessive clearance or restriction.
  7. Safety Features: It’s important to ensure that the combustion tube is designed with safety in mind. For example, the tube should have rounded edges to prevent injury during handling, and it should be labeled with relevant safety information, such as maximum temperature limits and handling precautions.
  8. Optional Features: Depending on the specific application, combustion tubes may have additional features, such as sidearm attachments for connecting to gas delivery systems or vacuum lines, graduation marks for measuring sample volume, or specialized coatings or treatments to enhance chemical resistance or durability.

Based on 2 reviews

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  1. Richard Vak

    Seamless ordering

    Richard Vak

  2. Ruth. k

    Indeed worth every penny

    Ruth. k