Titrimetric determination of phenol resorcinol and phloroglucinol.

A new and sensitive titrimetric method with an amplification procedure has been worked out for the determination of 10-1000 mug of phenol, resorcinol or phloroglucinol. The method is based on reaction of the phenols with an excess of bromine to form bromosubstituted aryl hypobromites. After removal of excess of bromine with formic acid, the hypobromites are treated with iodide to liberate an equivalent amount of iodine, which is extracted into chloroform, then reduced to iodide and determined by the Leipert procedure with 6-fold amplification. The coefficient of variation does not exceed 0.4% for amounts of determinand > 100 mug, but increases to 1.5% at the 10-mug level.