GC059 Internal Column Diameter (i.d.)

For fused silica columns, internal column diameter (i.d.) ranges from 100 to 530 µm (0.10-0.53 mm). Small i.d. columns (100 µm) produce fast analysis and good efficiency, but they can only manage small sample sizes, thus they are not well-suited for trace analysis. Additionally, special sample techniques and high-speed data systems are required to take advantage of their full potential.

Internal diameters between 250 to 320 µm represent the best compromise between resolution, speed, sample capacity and ease of operation. They can be regarded as the reference columns. A column of an internal diameter of 250 µm is a good starting point for general method development.

On the other hand, 530 µm or “wide-bore” columns have decreased resolution, but increased capacities and ease of operation. For example, direct on-column syringe injection is straightforward, and usually provides better quantitative results than packed columns.

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