Combating the Crud
Following on from my earlier post concerning the better ways of working with high matrix samples, I came upon an article on automated liner exchange in GERSTEL Solutions Worldwide; applied to the analysis of pesticide residues in food extracts.
We (Anatune) have had good experience of this approach. It offers a neat way of combining the benefits of simplified sample clean-up (low cost per sample and minimal loss of analytes) with good instrument up-time (due to high boiling and involatile material being constantly removed from the analytical system).
When running dirty samples on a GC-MS of any kind, careful choice of injector conditions (mainly temperature), means that you can easily retain involatile material in the liner.
This keeps your column and mass spec clean, but you will soon run into problems with the perfomance of the method due to interactions between analytes and the muck that is accumulating in the liner.
Ordinarily, this doesn’t offer much of a solution. It is highly inconvenient to have to interrupt a batch of samples and manually change the liner, every 10 samples or so.
However, if you automate the liner exchange procedure and build liner exchange in as part of your sample sequence, it suddenly becomes a very attractive way of working.
The GERSTEL ALEX is designed to perform automated liner exchange, in conjunction with a CIS 4 PTV Injector and Multi-Purpose Sampler. All of which fits nicely onto an Agilent 7890 GC. Here you will find a GERSTEL ALEX Leaflet that gives you some more information.
Chatting with Kaj Petersen of GERSTEL, I was surprised by how widely used automated liner exchange is in Germany and most are sold to labs doing pesticide residue work.
Anyhow, read the article attached to the email and see what you think.