乙酰丙酮分光光度法测定食糖中甲醛含量的研究

摘要

建立了一个检测食糖中甲醛含量的分光光度法.食糖样品溶于水后,加入磷酸,加热蒸馏,经水溶液吸收,馏出液中的甲醛与乙酰丙酮反应,生成黄色的化合物,该化合物在414 nm波长处有最大吸收,可用标准曲线法定量.该方法在1.0~50.0μg线性良好(R2=0.9999),检出限为0.2 mg/kg,分别在样品中添加甲醛标准品进行3水平加标回收实验(2、5、20 mg/kg),回收率为90.4%~98.2%,相对标准偏差为0.2%~4.3%(n=6).该方法样品前处理简单、快速,灵敏度、准确度和精密度均满足食糖中甲醛含量的检测要求.%A method was developed for the determination of formaldehyde in sugar by spectrophotometry. The sugar samples dissolved in water and added with phosphoric acid was distillated. The emitted formaldehyde was absorbed by cold water. The formaldehyde in the distillate was reacted with acetylacetone to form a yellow compound. The compound has the maximum absorption at the 414 nm wavelength and can be quantified by standard curve method. There was a good linear relationship between the absorbance and the content of formaldehyde in the range of 1.0~50.0μg (R2=0.9999). The limit of detection (LOD) was 0.2 mg/kg. The recoveries at three levels of 2, 5 and 20 mg/kg were from 90.4%~98.2% and the relative standard deviation (RSD) of 0.2%~4.3% (n=6). The method is simple, rapid and characterized with acceptable sensitivity, accuracy and precision to meet the requirements of formaldehyde analysis in sugar.