副玫瑰苯胺无汞比色法测定空气中的甲醛

在甲醛法测定空气中二氧化硫的基础上,建立了一种测定空气中甲醛的新方法。该方法所用设备和材料与甲醛法测定空气中的二氧化硫相同,不使用含汞试剂,用亚硫酸钠固定标准溶液和吸收液中的甲醛,用氢氧化钠分解羟甲磺酸释放已被固定的甲醛,以副玫瑰苯胺和亚硫酸钠为显色剂绘制标准曲线进行定量。当采集空气30L时,检出限为0.01mgm3,最低检测浓度为0.03mgm3,适用于环境空气及室内空气中甲醛的测定。

Determination of Formaldehyde in Air with Nonmercury Pararosaniline Colorimetric Method

A new method to determine formaldehyde in air is established ,based on determining sulfur dioxide in air with formaldehyde absorption solution. This method needs the same equipment and material as the formaldehyde method of determining sulfur dioxide in air needs, and no mercury reagent is used. In this method, sodium sulfite is used to stabilise formaldehyde in standard solution and absorption solution. Then, sodium hydroxide is used to release the combined formaldehyde. After coloration with pararosaniline and sodium sulfite, aborbance is measured and a standard curve is drew for the qualititative determination of formaldehyde. When the formaldehyde in 30L air is absorbed by absorption solution, the detection limit is 0.01mg/m3, and the minimum detectable concentration is 0.03mg/m3.This method is fit for determination of formaldehyde in ambient atmosphere and indoor air.