unkown peaks on contact fase

Dear collogues.
When I send my sample over the surface I get unknown peaks in begin and the end of association time.
Please, can some one give me a idea what happens ?
Thanks' in advance
Ricardo

Hi Racardo,
Spikes at the beginning and ending of the association phase are mostly induced by large buffer differences between running buffer and sample. Especially after subtracting a reference channel high bulk effect differences can cause these spikes. The best remedy is to change the buffer of the sample to match the running buffer.
The smaller spikes etc. can originate from the sample or running buffer that is insufficient degassed. In addition small aggregates can give bumps and spike. Therefore, spin down the analyte stock solution at 14000g for at least 5 minutes to pellet aggregates and degas the running buffer used for diluting the analyte.
Small spikes can also be an indication to clean your system.
Kind regards
Arnoud