The sorbent tube is glass with breakable end tips and contains a specially prepared high-activity sorbent. Most tubes have two sections, one for sample collection and one as a backup section. This configuration provides a check against saturation of the primary sorbent bed.
Some methods specify two separate tubes connected in series.
This allows the primary sorbent to be separated from the backup section to prevent sample migration during storage and transport. This Application Guide illustrates Sampling using Two Sorbent Tubes Connected in Series . 224-XR Universal Series Sampler with Adjustable Low Flow Holder Catalog No. 709, or SKC Film Flowmeter Cat. The sorbent sample tubes as specified in the method.