BSA-free blocker for saturating free binding sites on plastic surfaces or other protein binding surfaces Storage: 2 – 8 °C or -15 to -30 °C (tolerates repeated freezing and thawing cycles) contains < 0.0014 % [w/w] reaction mass of CMIT/MIT (3:1) Expiry date when stored unopened: see label on the bottle For general laboratory use Instructions for use SmartBlock™ is ready-to-use. Please shake the buffer thoroughly before use. Saturation / Blocking of microtiter plates 1. If the plate was treated with reagents containing detergents please wash the plate 3 times in a detergent-free wash buffer (e.g. Washing Buffer TRIS 10x without Tween, article no. 146 or Washing Buffer PBS 10x without Tween, article no. 141). If only a Coating Buffer (article no. 120 or 121) was used, aspirate Coating Buffer or empty plates by tapping firmly onto paper cloth. Add 200 - 300 µl SmartBlock™ per well. Incubate at room temperature for 1 - 4 hours or overnight. 1 hour is often sufficient. Note: The blocking time can be further reduced by shaking the plate at 600 900 rpm, depending on the application. The blocking time depends on the properties of the surface to be blocked and the ambient conditions and should therefore be tested. Aspirate SmartBlock™ or empty plates by tapping firmly onto paper cloth. Wash 3 times in wash buffer containing a non-ionic detergent (e.g. Washing Buffer TRIS, article no. 145, or Washing Buffer PBS, article no. 140). Saturation / Blocking of membranes 1. If the membrane was treated with reagents containing detergent please wash the membrane 3 times in a wash buffer free of detergents (e.g. Washing Buffer TRIS 10x without Tween, article no. 146 or Washing Buffer PBS 10x without Tween, article no. 141). Incubate membrane in SmartBlock™ at room temperature for 1 - 4 hours or overnight. 1 hour is often sufficient. The blocking time depends on the properties of the membrane and the ambient conditions and should therefore be tested. a) Wash membrane 3 times in a wash buffer containing a non-ionic detergent, (e.g. Washing Buffer TRIS, article no. 145 or Washing Buffer PBS, article no. 140). OR b) add antibody for detection and continue incubation and detection. V-01-

Suitability of SmartBlock™ for a specific assay has to be tested by the user. In case satisfying results cannot be obtained with the SmartBlock™ , e.g. if your assay measures analytes in plasma, serum or tissue specimen, we strongly recommend using The Blocking Solution (article no. 110). For further information please visit www.candor-bioscience.com.