Hi Khem B Adhikari,

While dealing with body fluids such as urine and serum for mass spectrometry analysis, care has to be taken for the salts present in the same. In case of urine, one can use 3kDa MWCO filter for getting rid of unnecessary salts and impurities. And sometimes its difficult to estimate the amount of protein using colorimetric assay such as BCA assay as there are interferring subastance present in urine which affects the reading. So its better to run a SDS PAGE gel using any standard marker such as BSA and determining the amount present in the urine.

Hope this helps!

Thank you.

Hi Varsa,

Thanks for your response but what I am asking is can we buy "urine controls" and "urine certified reference material" in the market which has a value analyzed in LC-MS platform?

Hi Khem,

Yes! Sure!

NIST has bunch of them: https://www-s.nist.gov/srmors/detail.cfm?searchstring=Urine

and more specifically: https://www-s.nist.gov/srmors/view_detail.cfm?srm=3667 and so on!

Thanks,

Biswa

Biswapriya Biswavas Misra

Thank you for your suggestions. I saw frozen urine SRM for a range of other metabolites, but NOT for cortisol.

I saw one with SRM 921 for cortisol but that is just in solution. I am looking for urine SRM for cortisol (urine SRM with specific cortisol level).

Any suggestions?

MVH

Khem