摘要
采用氧弹燃烧灰化法进行试样的预处理 ,使食品中的溴转化为离子状态 ,将燃烧产物用NaOH吸收后并在酸性介质中 ,先用H2 O2 氧化除去碘后 ,再用NaCIO氧化Br- 为BrO3- ,用HCOONa还原过剩的NaClO ,然后在盐酸介质中 ,以KCI为催化剂 ,借BrO3- 氧化亚甲蓝使褪色中吸光度的改变 ,利用分光光度法测定痕量溴。最大吸收波长λmax=6 6 8nm ,表现摩尔吸光系数为 4 .2 4× 10 4 ,BrO3- 浓度在 5× 10 - 8～ 1× 10 - 6 mol/L范围内符合比耳定律 ,回归方程为 :△A =9.372× 10 4 C + 0 .0 5 5 82 ,相关系数r =0 .9993。方法 ,应用于糙米和精中的总溴量得到了较好的分析结果。此方法具有简便 ,快速 ,准确 ,选择性好的优点。
A new method photometric method for determination of trace bromate in rice is proposed in the paper.At first,the samples were decomposed by the pretreatment technique of oxygen bomb fire ash and the production were absorbed by the thick and strong base,then in a acid medium,the I -1 were removed in by the oxidation of H 2O 2,the processing of the Br -1 were oxidated by the NaClO and the superfluous NaClO were by the HCOONa reduction.The optimum condition for oxidation of methylene blue in a hydrochloric acid medium by a BrO 3 -with sodium chloride as the catalyst were studied.The absorption maxima of the complex line at 668nm with a molar absorptivity of 4.24×10 4.Beer's law is obeyed over the range of iodide is 5×10 -8 ～1×10 -6 mol/L -1 .The regression equation is △A=9.372×10 4C+0.05582,the correlation coefficient is 0.9993.The method is accurate,quick and convenient .It is used in the determination of trace bromate in rice with satisfactory results.The method is simple,rapid,accurate and high selection.
出处
《中国粮油学报》
EI
CAS
CSCD
北大核心
2004年第3期82-84,共3页
Journal of the Chinese Cereals and Oils Association
