[RASMB] [Fwd: interference optics]

[Fumio Arisaka]

Dear RASMBers,

This concerns measurement of high concentrations of IgG with
interference optics. I have not much experience with IF, but
have started to use it for the necessity to measure high concentration
samples. Concentrations less than 5 mg/mL had no problem.
Attached jpg file is to show the problem at 10mg/mL. Somehow,
the boudaries tend to go horizontally before reaching the plateau.

I thought this was due to the misalignment of optics or something,
because the fringe pattern is not so good as I expect, but the
BeckmanCoulter person who came to fix it could not make it better.

I would like to know what is the common highest concentration
that you could measure by IF. As I understand one could measure
SE at higher concentrations than 100 mg/mL, but when the boundary 
gets too steep in SV measurement, the fringes get too much squeezed 
to count precisely.

Any comments and advice are highly appreciated.

Best wishes, Fumio




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