Fe3+催化二苯胺磺酸钠显色-分光光度法测定消毒液中过氧化氢

将1.00mL消毒液样品用蒸馏水稀释至100mL,取5.00mL,与5.0mL的8.0g·L^-1二苯胺磺酸钠溶液混合,加入3mol·L^-1 H2SO4溶液2mL,0.1mol·L^-1 FeCl3溶液0.5mL,用蒸馏水定容至50.0mL,室温下反应60min,以试剂空白作参比,用1cm的比色皿于波长410nm处测量吸光度。结果表明:过氧化氢浓度在0.116~1.16mmol·L^-1内与吸光度呈线性关系,检出限(3s/k)为0.02mmol·L^-1,表观摩尔吸光率为1.34×103L·mol^-1·cm^-1。方法用于测定消毒液中过氧化氢的含量,测定值与标示值相符,和碘量法的测定结果一致,测定值的相对标准偏差(n=6)小于2.0%。

Determination of Hydrogen Peroxide in Disinfectant by Spectrophotometry Based on Color Reaction of Sodium Diphenylaminesulfonate Catalyzed by Fe3+

The disinfectant sample(1.00 mL)was diluted to 100 mL with distilled water.5.00 mL of the solution was mixed with 5.0 mL of 8.0 g·L^-1 sodium diphenylaminesulfonate solution,and 2 mL of 3 mol·L^-1 H2 SO4 solution,0.5 mL of 0.1 mol·L^-1 FeCl3 solution were added.The volume of the solution was made up to50.0 mL with distilled water.After reaction at room temperature for 60 min,the absorbance was measured at the wavelength of 410 nm using a 1 cm cuvette with the reagent blank as a reference.The results showed that linear relationship was found between the absorbance of the solution and the concentration of hydrogen peroxide in the range of 0.116^-1.16 mmol·L^-1.The detection limit(3 s/k)was 0.02 mmol·L^-1 and the apparent molar absorptivity was 1.34×103 L·mol^-1·cm^-1.The proposed method was applied to determination of content of hydrogen peroxide in disinfectant,giving the measured value consistent with the labeled value and the determination result obtained by the iodometric method.The relative standard deviations(n=6)of the measured values were less than 2.0%.