Negative slope issues on Cary Workstation

Hi Everyone,

I'm operating our Cary 3500 and I am helping with an assay being put together based on competitive binding. Because of the competitive binding, the primary and reliable peak *decreases* in size rather than increasing as the concentration of analyte increases, because the analyte preferentially binds to the material activating the fluorophore and prevents activity from occurring within a fixed concentration of fluorophore. I realise there are some small inaccuracies inherent to such an assay design but allegedly this is necessary.

When I attempt to run a concentration curve with the instrument, the workstation software simply declares failed calibration on the basis of negative slope. Negative slope is somewhat unusual but in this case I would like to design a method that intentionally has a negative slope. Is there any way to do this with the device's native software, or will I have to export the results and analyse the values externally?

This seems like it should be quite straightforward, but I can't find any existing articles or advice on the subject.

Kind Regards,

Roland Kerr

Was this helpful?