Determination of Sulfite in White Granulated Sugar by Triethanolamine Sampling-pararosaniline Hydrochloride Spectrophotometry
YU Juan1,LU Jia-jiong2,GUO jian-xiong1 (1.China Sugar Inspection Center, Guangzhou, 510316 Guangdong Key Lab. of Sugarcane Improvement and Biorefinery;2. Light Industry and Food Engineering College, Guangxi University, Nanning, 530004;)
A new method was established to determine sulfite in white granulated Sugar by triethanolamine sampling-pararosaniline hydrochloride spectrophotometry, by using triethanolamine instead of mercuriate, the environmental pollution was less. Sulfur dioxide in samples reacted with triethanolamine to form steady compound. Adding formaldehyde, 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=0.9994) for the concentration of sulfur dioxide in white granulated Sugar ranged from 0～60mg/kg. RSD of samples ranged from3.1%～4.8%, the average recoveries of samples were between 93.3%～97.6%. The method detection limit was 0.50 mg/kg. There was no significant difference between the results by this method and those by the national standard method, the results were satisfying.