摘要
在弱酸性的HAc—NaAc缓冲溶液中，藻酸钠与乙基紫、结晶紫和甲基紫等三苯甲烷碱性染料发生反应，形成结合产物使染料发生褪色，且对于不同的染料，最大褪色波长分别为594nm（乙基紫体系）、584nm（结晶紫、甲基紫体系）、616nm（孔雀石绿体系）。藻酸钠浓度分别在0～5．0mg／L（乙基紫、甲基紫体系）、0～3．0mg／L（结晶紫体系）、0～2．0mg／L（孔雀石绿体系）范围内符合比耳定律；摩尔吸光系数根据染料的不同在3．6×10^5～4．8×10^6L·mol^-1·cm^-1之间，其中以乙基紫体系最灵敏，对藻酸钠的检出限为29ng／mL。以乙基紫体系为例研究了共存物质的影响。此法灵敏度高，选择性好，用于含藻酸钠的可立凝样品的分析测定，结果满意。
The reaction conditions, the spectrophotometric characteristics, and the analytical properties of the ion association complex of sodium alginiate with the basic triphenylmethane dye such as ethyl violet （EV）, crystal violet （CV）,methyl violet （MV）,malachite green （MG）,methyl green（MeG） and brilliant green （BG） were studied. The method was based on the discoloration reaction between sodium alginiate and triphenylmethane dyes in the pH 4.0 HAc-NaAc medium. The reduction in absorbance is directly proportional to the concentration of sodium alginiate and Beer＇s law is obeyed in the range of 0 -5.0 mg/ L sodium alginiate for EV and MV systems, 0-3.0 mg/ L for CV system, and 0-2.0 mg/ L for MG system, respectively. The molar absorptivities （ε） for different systems are between 3.6 ×10^5 and 4.8×10^6 L·mol^-1·cm^-1, and the EV system＇s is the highest. Taking EV system for an example, the effect of coexisting substance was investigated and the result showed that the method has good selectivity. The method has been used to determine the sodium alginiate with satisfactory result.
出处
《分析科学学报》
CAS
CSCD
2006年第6期679-682,共4页
Journal of Analytical Science
基金
国家自然科学基金(No.20475045)
关键词
褪色分光光度法
藻酸钠
三苯甲烷染料
Fading spectrophotometry
Sodium Alginate
Triphenylmethane dyes
