甲基橙-溴酸钾体系催化光度法测定废水中微量甲醛

根据在硫酸介质中，甲醛能催化溴酸钾氧化甲基橙溶液褪色，褪色程度与甲醛含量成正比，建立了催化动力学光度法测定微量甲醛的新方法。方法是体系溶液在50℃水浴中反应30min后加入抗坏血酸饱和溶液还原溴酸钾以终止反应，于最大吸收波长505nm处测量吸光度。溶液中甲醛浓度在0-2．0μg·mL。范围内呈良好的线性关系。用此法测定化工废水中微量甲醛的含量，RSD为2．97％（n=6），加标回收率在99．8％．106．9％之间。

Determination of Trace Formaldehyde in Wastewater by Methyl Orange-Potassium Bromate System Catalytic Spectrophotometric

A catalytic-kinetic spectrophotometric method was established for the determination of trace formaldehyde. In sulfuric acid medium, potassium bromate could oxidize and decolorize the methyl orange under the catalysis of formaldehyde and the decol-orization reaction was proportional to the content of formaldehyde. At 50 ℃ water bath for reaction 30min, ascorbic acid saturated so-lution was added into the system solution in order to reduce the potassium bromate and stop the reaction. Absorbance was measured at the maximum absorption wavelength of 505nm. The formaldehyde had a good linear relationship in the range of 0-2.0μg/mL. The method was used in determination of trace formaldehyde in chemical industry wastewater and the relative standard deviation was 2.97%（n=6）, the standard material recovery rate was between 99.8% -106.9%.