Biacore T00 salt build up on chip

      Hi,

I am currently using a Biacore T200 system and have been getting a build up of salt in two specific points on my sensor chips (image attached). This is resulting in my SPR traces having a constant negatively-trending baseline, I assume as the salt deposit is leached from the surface. I have tried the superclean and desorb & sanitize methods to stop this however it is still occurring. I have replaced the HBS-EP+ running buffer and tried new sensor chips which all result in this build up over a few hours. Any advice is welcome!

Thanks

Hi,
This is strange. Some questions.
1) Do you see the salt deposition when you take out the sensor chip?
2) Is the salt deposition wet or dry?
3) If you clean off the salt from the chip, dry it (not touching the chip) and insert it back have you still the drift?
4) What happens when you run water? is the chip clean when it comes out? if not, you can have salt deposits on the flow cell causing more deposits and possible leaking.

kind regards
Arnoud

Hi Arnoud,

1) Yes, the image of the sensor chip was taken after refreshing the buffers, placing a new cm5 chip into the system, running the "Prime", and then leaving the system overnight. I then ejected the chip this morning and the salt deposit was present

2) hard to say as I have tried to not touch the surface, however if I place the chip into buffer in a 50mL falcon tube it readily dissolves into solution

3) the drift returns fairly rapidly, as if there is a very small amount of salt remaining on the surface that I cannot visibly see

4) I will try running water tomorrow and see if this occurs - thank you for your help!