Hello Folks,
I am planning to measure the endogenous compounds (e.g.retinoids) in liver tissue with LC-MS/MS. But it is very hard to get a control matrix sample for method development and validation purpose. What is the best way to quantitate such endogenous compounds?
Many many thanks in advance.
Use common Waters or Agilent's methods (or variation for your sample matrix). See attached.
http://www.waters.com/waters/en_GB/Vitamins-/nav.htm?locale=en_GB&cid=134790609
Hi Naveen,
I guess it is difficult to find a stable liver standard that does not contain your retinoids, or contains them at a "known" level. I just added a comment about analyte standard additions. which can be used to calculate blank or baseline analyte levels in difficult matrices in Chen's question about endogenous compounds in food matrices (see link).
Regards, Tim Strutt
https://www.researchgate.net/post/Is_there_any_alternative_when_blank_matrix_for_endogenous_substance_which_is_not_availible_in_methodology_validation?_tpcectx=qa_overview_expertise&_trid=HRdm4ghJqZdRvxqdnEspUoda_6
Hello,
If I understand correctly- you need a "matrix" for method development. Is it for metabolomics kind of global profiling experiments or just vitamin focussed?
1. Why not get smaller aliquots of the true liver samples, mix all of them and always use them as a "pooled QC" for your method development (MRM?) or untargeted analysis.
2. For global profiling, you can use something like NIST Human Plasma: http://www.sigmaaldrich.com/catalog/product/sial/nist1950?lang=en®ion=US available from Sigma as a matrix. Or, this IROA Library would help: http://www.sigmaaldrich.com/catalog/product/sigma/msmls?lang=en®ion=US from Sigma as well.
3. If for profiling vitamin-specific compounds only get some of these stable isotope standards: http://www.sigmaaldrich.com/chemistry/stable-isotopes-isotec/stable-isotope-products.html?TablePage=21845686 from Sigma and use for method development.
Thanks,
Biswa
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