溴酚蓝共振瑞利散射光谱法测定痕量阳离子表面活性剂

在盐酸介质中,溴酚蓝(BromophenolBlue,BPB)和3种阳离子表面活性剂本身的RRS强度均很弱,但当它们依靠静电引力和疏水作用力相结合形成离子缔合物后,则可观察到共振瑞利散射强度急剧增强.考察了适宜的反应条件,影响因素及共振瑞利散射强度与阳离子表面活性剂浓度之间的关系,提出了用共振瑞利散射技术测定痕量阳离子表面活性剂的方法.方法的灵敏度高,检出限可达到纳克级,其中溴酚蓝-溴化十六烷基吡啶体系的灵敏度最高,其检出限可达3 1ng/mL,并且具有较好的选择性和较高的稳定性,用于合成水样和环境水样中阳离子表面活性剂的测定,结果令人满意.

RRS Method for the Determination of Cationic Surfactants with Bromophenol Blue

In dilute hydrochloric acid medium, the resonance Rayleigh scattering (RRS) intensity of alone bromophenol blue (BPB) or a cationic surfactant (CS) such as cetylpyridinium bromide (CPB), tetradecyldimethyl benzylammonium chloride (Zeph) and cetyltrimethylaamonium bromide (CTAB) is very weak. However, when they combine with each other to form an ionassociation complex, the RRS intensity is great enhanced and a new RRS spectrum appears. The characteristics of the RRS spectra of the ion-aasociation complexes and the optimum conditions for the reactions were investigated. The intensifies of RRS are directly mL-1 for different cationic surfactants. Under the reaction condition, most metal and non-metal ions do not interfere, so that the method has a good selectivity. Therefore, a sensitive, selective, simple and rapid method for the determination of cationic surfactants by RRS was developed. It was applied to the determination of trace amounts of cationic surfactants in synthetic water samples and environmental water samples with satisfactory results.