FIRST DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OF PHENOL AND HYDROQUINONE

Phenol and hydroquinone are directly determined at an acidity of pH≤7 by the first derivative UV spectrophotometry. Molar absorptivities of phenol and hydro quinone under lst derivation condition are found to be 5.0×10 4 and 4.2×10 4L·mol -1 ·cm -1 respectively, which are 34 and 19 times higher than those obtained by ordinary spectrophotometry. Detection limits of 0.04μg·ml -1 are found both for phenol and hydroquinone. The present method has been used in the analysis of some simulated samples containing both phenol and hydroquinone in different proportions. RSD′s for phenol and hydroquinone are less than 1.18% and 1.74% ( n =8) and the relative deviations are less than ±1.4% and ±0.80% respectively.