亚甲基蓝褪色分光光度法测定藻酸双酯钠  

Fading Spectrophotometric Determination of Alginic Sodium Diester with Methylene Blue

作　　者：李桂芝[1] 刘永明[1] 秦华伟[1] 

机构地区：[1]烟台大学化学学院,烟台264005

出　　处：《分析化学》2005年第9期1324-1326,共3页Chinese Journal of Analytical Chemistry

摘　　要：在pH为2.3的盐酸介质中,藻酸双酯钠与亚甲基蓝反应形成离子缔合物,使亚甲基蓝溶液褪色,最大褪色波长位于665 nm.藻酸双酯钠的浓度在2～8 mg/L范围内遵守郎伯-比尔定律,测定藻酸双酯钠的百分之一吸光系数ε0.01为6.39×102.该褪色体系操作简便,有较好的稳定性、选择性与准确度.据此直接测定了片剂中藻酸双酯钠的含量取得满意结果.In acidic solution （pH 2.3 ） alginic sodium diester reacts with methylene blue to form an ionassociation complex, which causes the fading of the methylene blue solution. The maximum fading wavelength is located at 665 nm, 60.01 is 6.39×10^2. The optimum conditions of the reaction, the influencing factors and relationship between the fading intensity and the concentration of alginic sodium diexter has been investigated. New method for determination of alginic sodium diester has been developed based on the experiments. The concentration of alginic sodium diester in the range of 2 -8 mg/L obeys Beer＇s law and the linear equation is A=-0.0639 CASD（mg/L） ＋1.507, r = 0. 9993. The detection limit is 0. 065 mg/L. The method with simplicity, stablility system, good accuracy and selectivity was applied to the determination of alginic sodium diester in tablets with precision of RSD 1.4% （n =6）. The recovery is 102.7% -98%.

关 键 词：分光光度法 亚甲基蓝 藻酸双酯钠 分光光度法测定 褪色 离子缔合物 盐酸介质 比尔定律 吸光系数 直接测定 

分 类 号：O657.3[理学—分析化学]