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Solution Preparation Calculator (% w/v)
Enter the target concentration and volume, and get the mass of solute to weigh in grams and the volume to top up to. 5% BSA blocking buffer, 0.9% NaCl and 10% sucrose all use the same formula.
Inputs
%
mL
Results
- Solute (weigh)
- 2.500 g
- Solvent (top up to)
- 50.0 mL
Formula
Solute (g) = Conc. (%) × Volume (mL) ÷ 100
Tip: Works for BSA / sucrose / NaCl etc. · Use fresh for stability
You got this step right, but a whole experiment has dozens of linked parameters. Change one dilution factor and everything downstream has to be recalculated. In Vara the parameters of your whole experiment are connected, so changing one recalculates the rest automatically. Manage 3 experiments for free.
FAQ
What does % w/v mean, and how do I make 5% BSA?+
% w/v is grams of solute per 100 mL of solution. 5% BSA means 5 g of BSA in every 100 mL. For 50 mL, weigh 5 × 50 ÷ 100 = 2.5 g of BSA, dissolve it in PBS or TBST and top up to 50 mL.
Why top up to the final volume instead of adding 50 mL of solvent?+
The solute takes up volume too. Dissolve it in slightly less solvent than the target, then bring the solution up to the final volume once everything is dissolved; otherwise the concentration ends up slightly low. BSA dissolves slowly and foams easily, so swirl gently or stir at low speed rather than vortexing.
Can I prepare BSA blocking buffer ahead of time?+
Prepare it fresh and use it the same day when possible. Protein solutions are a good growth medium for microbes and can become contaminated after a few hours at room temperature. If you must store it, keep it at 4 °C for no more than a few days, or freeze single-use aliquots and do not refreeze after thawing.