改进MBTH分光光度法测定室内空气中甲醛的含量

改进了MBTH（酚试剂）测定室内空气中甲醛的方法。用乙醇做溶剂制备酚试剂吸收液,稳定性和灵敏度增强,优化了测定条件,最大吸收波长633 nm,显色温度20～25℃,显色时间25 min,显色剂用量2～2.5 mL,加标回收率达到96%以上,样品测定结果与国标偏差不超过3%,适用于甲醛含量测定;根据颜色对应的浓度制作比色卡。该方法精密度高、准确性好,简单、快速,可用于空气中甲醛含量的测定。

Determination of Formaldehyde in Air Indooor with Improved MBTH Spectrophotometer

The MBTH speetrophotometric method for the determination of formaldehyde in the air indoor was improved.The stability and sensitivity of the MBTH liquid dissoluted with ethanol was better than that dissoluted with water.Determination conditions were optimized.The absorption peal was at wavelength of 633 nm,temperature was 20~25 ℃,time was 25 min and volume of chromogenic agent was 2~2.5 mL,under which the recovery rate was more than 96% and sample results was not more than that was determined with national standards.Color card was made according to different concentrations.The result indicated that the improved method could be applied to determine formaldehyde in air indoor.