Good day,

I prepared a K-Gluconate based internal solution which has a final osmolariry of 360 mOsm while I was expecting something around 300mOsm.

It contains

170 K-gluconate, 10 HEPES, 5 NaCl, 10 KCL, 0,6 EGTA, 2 Na2ATP, 0,3 NaGTP, 10 NaPhosphocreatin

I was not comfortable to add water to my stock solution so I aliquoted it and put it at -20, thinking that I could add a bit of water to each aliquot when needed.

Do you think working with such a high osmolarity could be a problem (I will tomorrow measure the osmolarity of my ACSF) ?

How do you normally decrease the osmolarity without changing the ions concentration ?

Thanks for your help !