m-Aminophenylarsonic acid as a reagent for the extraction preconcentration of phenol

The azocoupling reaction of phenol with the diazonium salt of m-aminophenylarsonic acid was used for the determination of phenol in water at a level of maximum permissible concentrations. The resulting compound is stable in a wide pH range, which made it possible to develop a procedure for the determination of phenol with the preconcentration of the azo compound by extraction to isobutanol at pH 2 and subsequent back extraction to the aqueous phase at pH ≥ 10. The high concentration coefficient of phenol (65) provides for determination of phenol down to 0.9 μg/L.