Hello,
I extracted my PDMS passive sampler with ethylacetate for analysis of a wide spectrum of compounds present in the environment using GC Orbitrap. Unfortunately my samples are contaminated with siloxanes, which are interfering with my massspectrometry. Is there a way to clean my sampels selectively from siloxanes with a decent recovery of my other analytes?
Hello, are you sure that's it contamination, may be siloxanes comes from your GC column due to use aggressive solvent or higher temperature of column. Also problem may come if your column is new and not preconditioned before use.
In in addition to Karen's input, they may also come from the inlet septum, if this has a significant number if injections. So in order to decrease siloxanes, be sure to do full standard maintenance (I.e. new septum and liner) and if the column is old, replace with a new and bake it out. You will never get rid of it fully, but you can reduce the impact.
That being said, you are bound to co-extract siloxanes from PDMS. What type of compounds are you trying to detect? Maybe another sampler lile e.g. activated charcoal could be more suitable. To avoid interference. A different column may also be able to separate analytes and contaminants in a more satisfactory manner.
Hi Theo,
I would also check for column/septum bleeding. Take a look at this link:
https://blog.restek.com/?p=10706
Theo,
You could also consider trying Amberlite XAD active samplers. I have used them for both PCB's and PAH's. Recovery is quite good and adsorption is done easily with eg. a 1:1 of acetone and a suitable n-alkane (we used pentane) using a combination of mechanical shaking and ultrasound.
https://www.academia.edu/12461636/Sample_preparation_for_chromatography_book
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