Spotting Capillary
Spotting capillaries are typically produced by tangentially connecting glass capillary tubes and pipettes. The manufacturing process involves three main steps: tip treatment, tube wall protection, and filling. Among these, tip treatment is critical, as the shape and size of the tip significantly influence the quality and stability of the capillary tube.
Sealed Melting Point Capillary
The sealed melting point capillary tube is produced through a melting point welding method. This involves heating and thermally overlapping two glass capillary tubes, bonding them at high temperatures to create a closed structure. While this method ensures excellent sealing performance, it also results in higher production costs.

Structural Differences
Spotting Capillary
Spotting capillaries have a simple structure with thin walls, making them ideal for handling small sample volumes.
Sealed Melting Point Capillary
Sealed melting point capillaries feature a more complex structure with thicker walls. Multiple production processes are required to ensure reliable sealing performance, enhancing their robustness for certain applications.
Applications
Spotting Capillary
Spotting capillaries are primarily used in gas chromatography and microanalysis, meeting the demands for high sensitivity and excellent separation of samples.
Sealed Melting Point Capillary
Sealed melting point capillaries are typically utilized in liquid chromatography and high-performance liquid chromatography (HPLC). Their sealed structure prevents issues such as sample volatilization and low solubility, resulting in improved analytical performance.
Spotting capillary tubes and sealed melting point capillary tubes differ significantly in terms of production methods, structural design, and applications. By understanding these distinctions, scientists can choose the appropriate type of capillary tube based on their specific analytical requirements, ensuring accurate sample analysis and precise quantitative detection.