10X PBST Buffer, pH 7.4, 8 X 500mL" Specification Value Concentration 10X Name PBST Buffer pH at 1x pH 7. 4 0. 2 Volume 8 X 500mL SKU PBT 10 0400 Composition at 1x NaCl 1. 37 M, KCl 27 mM, phosphate buffer 100mM and Tween 20 0. 5% A phosphate buffered saline solution with Tween 20 detergent, widely used as a washing buffer in ELISA, western blotting, and immunohistochemistry. The addition of Tween 20 effectively reduces non specific binding while preserving specific antibody antigen