亚甲基蓝-甲基橙混合指示剂测定三次采油用石油磺酸盐有效物含量

以海明1622为滴定剂，以亚甲基蓝一甲基橙混合物为指示剂，采用两相滴定法，测定了三次采油用石油磺酸盐中有效物的含量通过对影响滴定因素的考查，确定了滴定分析条件。结果表明：当亚甲基蓝与甲基橙的质量比为5：1，配成含有0.1％亚甲基蓝和0.02％甲基橙的混合指示剂，加量在4～8滴，可以明显地观察到终点颜色变化，其变化特点为上相由粉红色至蓝色，下相由蓝色至绿色。用该方法测定三次采油用石油磺酸盐有效物含量，终点清晰，干扰小，操作简便，重现性好，其相对标准偏差小于1.0％。

Two-phase titration using mixed indicator of methylene blue and methyl orange to determine the active matter among PS

This paper introduces the two- phase titration method,which uses hyamine 1622 as the titrant,the mixture of methylene blue and methyl orange as the indicator,to determine the active matter among PS (petroleum sulfonate) employed to enhance oil recovery.By studying the factors affecting titration results,we optimize the titration condition and prepared the mixed indicator solution which contains 0.1 wt% methylene blue and 0.02 wt% methyl orange (the concentration ratio of two indicators is 5:1). The investigation shows that,with the addition of 4-8 drops of the mixed indicator,when the end- point is obtained,the pink color of the aqueous phase becomes blue and the blue color of the chloroformic phase becomes green.The both color change can be observed clearly.The two- phase titration has many advantages such as obvious end- point,low disturbance,easy- to- operate and good repeatability.In addition,its relative standard deviation is less than 1.0%.