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Measurement of conjugated antibody metal content with Helios

PostPosted: Thu Mar 02, 2023 11:38 am
by JennyChuang
Hi all,

I would like to determine how many metal ions are on an in-house conjugated antibody using Helios.
I've prepared 2% HCl and 2%HNO3 for digestion and dilution, and Tuning solution as the standard.
Does anyone know the exact concentration of isotopes in the tuning solution and how to calculate the result after acquisition?
In addition, I would be very grateful if you could share the instrument setup step for Helios( I think it should use the solution mode.)

Thank you very much


Re: Measurement of conjugated antibody metal content with He

PostPosted: Thu Mar 02, 2023 4:00 pm
by CRStevens
Hi Jenny,

To my knowledge the tuning solution has 0.5ppb 159Tb in it. I do caution you, though, that if your metal on your antibody is not 159Tb, you should not use tuning solution as a standard and purchase a standard for that particular metal from inorganic ventures.
I've been using this one..... It has a bunch of lanthanides in it, and they are all at 10ppb, so just need to dilute to 0.5ppb. I usually do a standard of 200, 100, 50, 25, 12.5 ppb for my standard curve. ... -std-125ml

also, as a side note. If your metal is not monoisotopic you have to account for natural abundance of your isotope, because these particular standards are not isotopically pure. For instance, Eu will have both 151 and 153 in their corresponding natural abundance.

Re: Measurement of conjugated antibody metal content with He

PostPosted: Fri Mar 03, 2023 9:56 am
by JennyChuang
Hi Chad,

Thank you for your answer. That helps a lot!
I would ask to purchase the standard that you've been using!

And thank you for providing the protocol of Ab digestion.
I really appreciate that!
It's a bit different from the protocol from Fluidim but I'll test both.
However, could you share the DVS worksheet with me if you can find that?
I think I got the protocol from DVS but I could not find the spreadsheet.
I would like to double-check the formula just in case I got the wrong calculation.
Thank you again.