表面活性剂对钙指示剂影响的研究

Study on effects of surfactants on Cal-Red

由于钙指示剂(又称NN指示剂)的水溶液不稳定,通常将其配制成固体指示剂使用,但是存在着生成的络合物不够稳定、终点变色不敏锐、准确度不高等问题。研究了固体钙指示剂的最佳使用条件,以及表面活性剂对钙指示剂稳定性、灵敏度的影响等问题。实验结果表明:固体钙指示剂的最佳配比是钙指示剂与氯化钠的质量比为1∶100、液体钙指示剂中钙指示剂-十二烷基硫酸钠,以及钙指示剂-乳化剂OP-10-苦味酸效果最佳,终点变色更加敏锐,精密度以及准确度都有显著提高,体系稳定性好。

Cal-Red（also known as NN indicator） is often prepared to solid indicator because its solution is unstable.But because the produced complex is not stable enough either,the indicator′s titration end point is not clear and the accuracy is poor.The optimum working conditions of solid Cal-Red as well as the effects of surfactants on the stability and sensitivity of Cal-Red were studied.The experimental results showed that the optimum mix for solid Cal-Red is m（Cal-Red）∶m（NaCl）=1∶100;and for liquid Cal-Red,the mixture of ＇Cal-Red-sodium dodecyl sulfate＇and＇Cal-Red-emulsifier OP-10-trinitrophenol＇had the best effect.Under the optimum conditions,not only the terminal color-changing was acute,but also the accuracy and precision were improved a lot and system was more stable.