活性炭富集光度法测定水中痕量苯酚

PHOTOMETRIC DETERMINATION OF TRACE AMOUNTS OF PHENOL IN WATER AFTER ITS ENRICHMENT WITH ACTIVE CARBON

水中痕量苯酚用粒度≤80μm的活性炭从pH6左右的介质中吸附富集，并用50g·L^-1氢氧化钠解吸后从pH4的磷酸溶液中蒸馏分离。分取部分馏出液，在氨性缓冲介质中使苯酚与4-氨基安替比林和铁氰化钾反应生成橙红色络合物，在510nm波长处对试剂空白测定其吸光度，标准曲线用苯酚标准溶液制备，其线性范围为0．5～12．5μg（52．5mL显色液中）。方法的检出限为2．9×10^-6g·L^-1，应用此方法测定了4种水样中的苯酚，相对标准偏差在3．5％～4．7％之间，回收率在92％～107％之间。

Trace amounts of phenol in water were enriched by adsorption on active carbon （graininess ≤80 μm） in an acetate buffer medium of pH 6. The enriched phenol was desorbed from active carbon with 50 g · L^-1 NaOH solution. The alkaline solution was adjusted to pH 4 with phosphoric acid, and phenol was separated by distillation. An aliquot of the distillate was taken and reacted with 4-amino-antipyrine and potassium ferricyanide in an ammoniacal buffer to give an orange-reddish colored complex, the absorbance of which was measured at the wavelength of 510 nm using a reagent blank as reference solution. Calibration curve was prepared with standard phenol solutions in the concentration range of 0. 5 to 12. 5μg per 52. 5 mL of the colored solution. Detection limit of this method was 2. 9× 10^-6g· L^-1. In the analysis of 4 water samples for their phenol contents by this method, RSD＇s （n=7） found were in the range of 3. 5%-4. 7%, and recoveries in the range from 92%-107%.