Key TD standard methods (e.g. ISO 16017 and US EPA Method TO-17) recommend that liquid- and gas-phase standards are loaded onto the sampling end of clean sorbent tubes in a stream of carrier gas using unheated apparatus.


Markes’ Calibration Solution Loading Rig (CSLR) has been specifically designed for loading sorbent tubes with gas- or liquid-phase standards. It has a flow-path constructed of stainless steel and consists of an unheated injector port with a controlled carrier gas supply. The sampling end of a packed sorbent tube is connected to the CSLR by a ¼″ brass nut and PTFE ferrule.


The carrier gas flow is adjusted using a needle valve, and is normally set between 50 and 100 mL/min, according to standard methods. This sweeps the injection port and carries the standard into the sorbent tube. The calibration standard (gas or liquid phase) is introduced through the injector septum using an appropriate precision syringe. The compounds of interest are swept onto the sampling end of the attached tube in the stream of carrier gas, and reach the sorbent bed in the vapour phase.

Advice on routine calibration of TD methods is given in Markes’ Application Notes TDTS 7 and TDTS 75 


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