间接原子吸收光谱法测定食品中甲醛的含量

Determination of Formaldehyde in Food by Indirect AAS

本文建立了一种食品中甲醛含量测定的新方法——间接原子吸收光谱法.甲醛与高锰酸钾在热水浴(40℃)中反应35 min生成二氧化锰沉淀,将沉淀洗涤溶解后,测定Mn^(2+)的吸光度,从而间接求得食品中甲醛的含量.实验着重考察了高锰酸钾用量、反应时间、离心时间、反应温度、浓盐酸用量及酸度对结果的影响,选取反应在40℃进行35 min,离心时间8 min,物质的量浓度为0.02 mol·L^(-1)的高锰酸钾溶液0.8 m L,浓盐酸2 m L以及中性条件.锰的质量浓度在4μg·m L^(-1)以内与吸光度呈线性关系.

A new method to determine formaldehyde by indirect atomic absorption spectrometry（ AAS） was established. The reduction of Formaldehyde was reacted with potassium permanganate ＇s solution in a thermostat water bath for 35 min to give MnO_2 precipitation and determined by AAS. The amounts of Mn found were converted to content of formaldehyde in food. Several parameters affecting the determination were studied,including effect of the mount of potassium permanganate,reaction time,centrifugation time,reaction temperature,the mount of of hydrochloric acid and acidity. The reaction was carried out using 0. 8 m L of 0. 02mol·L^（-1） potassium permanganate solution in pH 7. 0 at 40 ℃,and the reaction time was 35 min,the centrifugation time was 8 min.Linear relationships between values of absorbance and mass concentration of Mn was obtained in 4 μg·m L^（-1）.