Determination of Volatile Phenol in Waste Water of Petro-refinery by the Automatic-Intermittent Analyzer

Waste water sample (250 mL) was distilled at pH 4.0 in the presence of CuSO4 (0.5 g), and volatile phenol in an aliquot of the distillate (250 mL) was determined by the Clever-chem 200 analyzer automatically. The color reaction of phenol with alkaline solution of K3Fe(CN)6 at pH 10.3 (R1) and solution of 4-amino-antipyrine (R2) to form red colored compound with λmax at 510 nm adopted by the analyzer. An aliquot of 200 μL of sample solution and 90 μL of R1 as well as 135 μL of R2 were used in the analyzer. Linearity range for phenol was kept between 0.05 to 2.00 mg·L-1, with detection limit (3s/k) of 0.005 mg·L-1. Tests for recovery and precision were made by standard addition method, giving values of recovery in the range of 94.7%-108% and RSD′s (n=6) ranged from 2.6% to 6.3%. Analytical results found by the analyzer were in consistency with those found by the GB standard method.