甲醛溶液吸收-盐酸副玫瑰苯胺分光光度法测定白砂糖中的二氧化硫

本文建立了用甲醛溶液吸收-盐酸副玫瑰苯胺分光光度法测定白砂糖中二氧化硫的方法.该法用甲醛代替汞盐,减少了对环境的污染.样品经处理后加入甲醛,样液中二氧化硫与甲醛生成稳定的羟基甲基磺酸,加氢氧化钠后,与盐酸副玫瑰苯胺作用,生成紫红色化合物,在579 nm处测定其吸光度.白砂糖中二氧化硫浓度在0～60 mg/kg范围内与吸光度值呈良好的线性关系(r=0.9998),检出限为0.81 mg/kg.样品测定的相对标准偏差在2.8%～4.1%,回收率在93.8%～98.6%之间.与国标方法测定结果比较,两者无显著性差异,结果令人满意.

Determination of Sulfite in White Granulated Sugar by Formaldehyde Solution Sampling-pararosaniline Hydrochloride Spectrophotometric Method

A new method was established to determine sulfite in white granulated Sugar by formaldehyde solution sampling-pararosaniline hydrochloride spectrophotometric method.Using formaldehyde solution instead of mercurate,the environmental pollution was reduced.Sulfur dioxide in samples reacted with formaldehyde to form steady hydroxyl ethlsulphonic acid.Adding sodium hydroxide,the compound reacted with pararosaniline hydrochloride to produce one purple red compound,which was determined by spectrophotometry at 579 nm.This method had good linearity(r=0.9998) for the concentration of sulfur dioxide in white granulated Sugar ranged from 0-0.06 g/kg.RSD of samples ranged from 2.8%-4.1%,the average recoveries of samples were between 93.8%-98.6%.The method detection limit was 0.00081 g/kg.There was no significant difference between the result by this method and those by the national standard method,the results were satisfying.