Can the industry-standard (¼-inch (6.4 mm) o.d. x 3½-inch (89 mm) long) sorbent tubes be used with OPTIC?


Analytical thermal desorption, known within the analytical chemistry community simply as "thermal desorption" (TD), is a technique that concentrates volatile organic compounds (VOCs) in gas streams prior to injection into a gas chromatograph (GC). It can be used to lower the detection limits of GC methods, and can improve chromatographic performance by reducing peak widths. (Wikipedia)


The ¼-inch sorbent tubes (thermal desorption tubes) can only be used in the special OPTIC-4 1/4 Inch version , this version of the OPTIC-4 has an inlet body that can adapt  Thermal Desorption (TD) tubes of ¼-inch x 3½-inch.

Metal TD tubes cannot be used with the OPTIC-4 inlets when delivered before July 2021. Starting from July 2021 we have changed the inlet design and now we are able to work with metal tubes. 

The standard OPTIC-4 cannot handle the ¼-inch tubes, this version inlet is made for liner of OD 5 mm and L 81 mm. And the ¼-inch OPTIC version cannot handle the 'standard' liners (OD of 5 mm).

For automatic liner exchange, there is also a LINEX  and CDC  available for the ¼-inch tubes. 

The standard liner for the standard OPTIC is 81 mm long and OD is 5 mm.
The TD tube for the 1/4 Inch OPTIC is ¼-inch x 3½-inch = 6.4 mm x 89 mm.

Our liners / TD tubes can be found here.


The advantage of using the OPTIC of TD applications is that the desorption happens on top of the column. The transfer of the compounds from the tube to the column are done here in the best way. With the cryo-trap option the compounds can also be refocus on the fits part of the column resulting in very nice sharp peaks in the chromatogram.