PerkinElmer’s automatic verification method described in the patent is deployed in the Company’s TurboMatrix™ Thermal Desorber product line of GC systems to help users avoid manual errors in ATD measurement, which can cause inconsistent results and compromise sample integrity. The method was co-invented by Andrew Tipler, senior scientist, gas chromatography, PerkinElmer, and Neil Plant, senior scientist, Health and Safety Laboratory, Buxton, United Kingdom.
“In the past, analysts had to be concerned that their results could be affected by lack of integrity of the packing materials in ATD tubes and traps,” said Tipler. “Our automatic method for checking the packaging integrity helps our customers maintain a high level of confidence in their analytical results, ultimately helping them to save time and increase lab productivity. The method is already incorporated in our TurboMatrix Thermal Desorber line, which can be used in a wide range of industries and applications.”
PerkinElmer first introduced ATD in 1982 as an effective method for isolating volatile compounds from various gaseous matrices so they can be introduced as samples into a GC instrument. It is the most popular technique for both indoor and outdoor air monitoring and is also used for analysis of soil, water, biofuels, polymers, packaging materials, flavors and fragrances, cosmetics, pharmaceuticals, and many other applications.
ATD works by drawing a vapor sample through a thermal desorption tube that is packed with one or more adsorbents. The tube is heated to release volatiles from the packing, which are swept into a cooled secondary trap. This trap is then rapidly heated to desorb the collected components into the GC column for separation and identification. These tubes and traps need to be packed consistently to provide the same sampling and thermal desorption flow rates and flow paths for each analysis run. If there are voids in the packing material or absorbents become frail and fragment, gas flow can become channeled or blocked and analytical results can be inconsistent.
In the past, analysts sometimes manually measured the flow impedance of tubes to validate their performance, but this process is time-consuming and the traps are not easily accessible. Tipler’s and Plant’s automated method for monitoring the flow impedance of thermal desorption tubes and traps alleviates this problem. When the method is implemented, the user is alerted when thermal impedance moves outside of preset boundaries, which can usually be resolved by repacking or replacing the tube or trap.