Evaporation, semi-micro

Evaporate the combined extracts on a water-bath under a jet of air to about 3 ml, completely transfer the residue with small portions of chloroform to a tared 50-ml beaker, and heat again to evaporate the solvent completely. Heat further at 105° for thirty minutes, cool in a desiccator and weigh the residue of triacetyl adrenaline. Add 5 0 ml of chloroform, cover the beaker, gently swirl until the residue is completely dissolved, and detennine the specific rotation, Ry using a 2-dm, semi-micro polarimeter tube. 

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