This is a 10X concentrated liquid reagent for washing EIA plates/membranes, applicable in both manual and automatic ELISA and blotting protocols. Mixing 1 part buffer with 9 parts pure deionised water will produce 10 parts of ready-to-use Wash Buffer comprising ~0.15M PBS pH 7,2-7,4 plus 0.05% Tween-20 preserved with 250 ppm BND.