近红外花菁共振光散射法测定阴离子表面活性剂

Determination of Anionic Surfactant by a Resonance Light-scattering Technique Using a Near-infrared Cationic Cyanine

应用共振光散射光谱研究了pH6.30磷酸盐缓冲介质中近红外阳离子花菁染料与阴离子表面活性剂的相互作用.由于形成离子缔合物,花菁的聚集形态发生了变化,导致共振光散射增强,最大散射峰波长位于823nm;根据共振光散射强度的增加值与加入的SDBS的浓度间存在的正比关系,建立了共振光散射法测定阴离子表面活性剂的新方法.考察了pH值、有机溶剂用量等对测定的影响.在最佳实验条件下,对SDBS检测的线性范围为4.0×10-8-6.0×10-6molL-1,检出限为1.4×10-8molL-1,相关系数r=0.9988.该方法简单快速,具有较高的分析灵敏度,用于环境水样中阴离子表面活性剂的测定,结果令人满意.

The interaction between cationic cyanine dye and anionic surfactants sodium dodecyl benzenesulphonate （SDBS） in the phosphate buffer medium was studied using the resonance light scattering （RLS） technique. Due to the formation of the ion association complexes, the aggregations of cyanine have been changed, which result in the RLS enhancement with the maximum RLS peak at 823nm. And the enhanced intensity of RLS is proportional to the concentration of SDBS. Thus, a novel method for the determination of SDBS was developed. Also the effect of pH, organic solvent on the determination have been investigated. Under the optimum experimental conditions, the linear range is 4.0×10^-8-6.0×10^-6molL^-1 for SDBS, the detection limit is 1. 4 ×10^-8molL^-1 and the correlation coefficient is 0. 9988. This method is simple, fast and sensitive. It was applied to the determination of trace amount of anionic surfactants in environmental water samples with the satisfactory results.