The estimation of basic groups in wool by dye-uptake measurements

The rate of uptake of acidic dyes (acid form) by wool from aqueous solution is markedly increased by the presence of hydrogen-bond-breaking reagents. Wool absorbs Orange II very rapidly from solutions in anhydrous formic acid. At solution concentrations above 3 meq./l., the uptake is constant at 0.83 meq./g. Merino 64's wool which corresponds to 1 equiv. of dye per basic group. The technique is applicable also for the estimation of basic groups in chemically modified wools.