What is Capillary?

According to The American Heritage Dictionary, Capillary is defined as "Any tube with a small internal diameter".¹ In the realm of analytical chemistry and spectroscopy, capillary is understood to be small internal diameter glass tubing. The most highly specialized glass capillary is referred to as Flexible Fused Silica Capillary Tubing. It is synthesized from highly purified silica and externally coated with a protective polymer to yield a strong, durable, and yet flexible tube that is used across a wide range of applications.

Flexible synthetic fused silica capillary tubing from Polymicro is manufactured across a range of internal diameters from less than 1.0mm to over 2000mm (PT standard: 2mm to 700mm). Standard capillary is fabricated from synthetic fused silica preforms using sophisticated draw towers and following closely controlled manufacturing processes. The outside silica diameter typically ranges from 90mm to >3500mm (PT standard: 90mm to 850mm). In most applications, an external polymer or metal coating is applied to protect the silica outer diameter from abrasion. The coating thickness will depend on the material and application. Similar tubing can be manufactured using natural quartz, borosilicate glass, or doped synthetic fused silica materials depending on the application requirements. Polymicro manufactures only the highest quality fused silica, doped fused silica, and speciality natural quartz capillary.

¹ The American Heritage Dictionary, Houghton Mifflin Company, Boston, 1981