萃取-光度法测定阴离子表面活性剂通常以次甲蓝为试剂,由于此法有操作复杂、灵敏度不太高等缺点,近几年有不少使用它种试剂的研究。田口茂等用双-2-(2-吡啶偶氮)-5-二乙氨基酚钴(Ⅲ)盐酸盐〔Co(PADAP)_2〕C1为试剂进行测定,并对其某些类似物作了研究。 Co(PADAP)_2~+在强酸介质中不被分解,具有较高的摩尔吸光系数,与阴离子表面活性剂形成离子对后能为苯等溶剂萃取,但对短碳链表面活性剂萃取能力很差,因此用它测定 Extraction - photometric determination of anionic surfactants usually methylene blue as a reagent, because of this method has complex operation, the sensitivity is not too high shortcomings, in recent years, there are many studies using its reagents. Taguchi and others used bis (2- pyridylazo) -5-diethylaminophenol cobalt (III) hydrochloride [Co (PADAP) 2] C1 as a reagent for the determination of some of its analogs Study. Co (PADAP) _2 ~ + is not decomposed in strong acid medium, and has a high molar extinction coefficient. After forming ion pairs with anionic surfactants, it can be extracted by benzene and other solvents, but its ability to extract short chain surfactants Poor, so use it to measure