determine linearity, LOD, LOQ, accuracy and precision.
You need some matrix to determine whether it has any effect.
There are two great ways to identify matrix effects in your MS. Inject a prepared blank matrix sample while infusing your analyte post column. This will give a graphical display of where your greatest matrix effects on the MS occur, and you can then optimise your method to avoid these areas if possible. Alternatively you can prepare 2 identical spiked samples, one with matrix and one in your LC solvent. The ratio of the responses tells you the magnitude of your matrix effects on the MS. The disadvantage with this method is you need to have done most of you method development by this stage.
Hi Richard
The first method you mentioned, which is to infuse post column while injecting blank matrix through the column, can you suggest a reading material for it, such as a research article or presentation? Thank you.
For a web-based view try the following link from LCGC magazine (Chromatography online)
For a book chapter try Tandem Mass Spectrometry - Applications and Principles ISBN 978-953-51-0141-3
Both give a reasonable overview of ion suppression and how to evaluate.
Good luck
Richard
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0ahUKEwjEjrWl8rbNAhVBIcAKHeX0BYQQFgg8MAQ&url=http%3A%2F%2Fquimica.udea.edu.co%2F~carlopez%2Fcromatohplc%2Fion_supression_lcms_2006.pdf&usg=AFQjCNEPx-xar-D3pGNPeezxYMdcYQJlBg&bvm=bv.124817099,d.ZGg
http://www.chromatographyonline.com/ion-suppression-major-concern-mass-spectrometry
Hi Richard,
My question was ....what if you do not have internal standards and blank matrix?
Hi
You don't need an internal standard, you can assess the likely effect on your principle analyte. Without matrix it is a little more difficult, but not impossible. If you can get a similar material to your matrix this will give you a starting point. It may be possible to prepare a synthetic matrix (you don't say what your matrix or analytes are) that will approximate your actual matrix and at least give you a starting point to work from. For example, we have used a synthetic saliva to provide calibrators.
Usually the greatest matrix effects on the MS occur early in the chromatographic run, so you can optimise the run to have the analyte elute after at least 10 column volumes - it may not eliminate all matrix effects but should reduce the worst of them.
Richard
Hi, Richard, my analytes are pharmaceuticals...and my matrix is wastewater from Hospital and wastewater treatment. Determination of Pharmaceuticals in wastewater. Do you think I can synthesize the matrix?
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