Dear all,

For some time now, we have major problems with flow cytometry measured signal intensities in staining of a protein within the nucleus. All extracellular stainings are unchanged.

After various experiments with different technical changes (temperature 4°C and 20°C and also in time), finally we noticed that the pH value of the Foxp3 buffer component is probably not correct (?).

According to the manufacturer's specifications, all three components of the eBioscience Foxp3 buffer set have pH values of 7.2 - 7.4.

12746048 (Fixation/Permeabilization Diluent 100ml) - is ok!

12766048 (Permeabilization Buffer (10X) 100ml) - is ok!

12736048 (Fixation/Permeabilization Concentrate 30ml) *is pH=4.5 or lower.

We are not be aware if this cause decreased signal intensities!

Unfortunately the inquiries about the german distributor take too long and for this reason we would like to ask, if any of you can measure the pH-value of this buffer component and tell us the result.

Thanky you very much for your help.