差示光度法中的标准加入法测定水泥中的MgO  

A standard addition method for differential spectrophotometric determination of magnesium oxide in cement

作　　者：任树林[1] 张斌[1] 

机构地区：[1]延安大学化学与化工学院,陕西延安716000

出　　处：《化学试剂》2008年第1期26-30,共5页Chemical Reagents

摘　　要：研究了用铬黑T做显色剂，以EGTA掩蔽干扰离子，用差示分光光度法中的标准加入法测定水泥中的氧化镁。在pH10．5的NH3-NH4C1缓冲溶液中，铬黑T与镁形成稳定的配合物，其最大吸收波长是530nm；镁在0．06-0．5μg／mL范围内符合朗伯-比尔定律，摩尔吸光系数ε为2．23×10^4L·mol^-1·cm^-1。该方法测定时间短，操作简便，不仅能用来测定高浓度的物质，而且还可以消除背景的影响，所用试剂及仪器价格低廉。This article refers to a method for determining magnesium oxide in cement with Erichrome black T,using EGTA to mask the disturbance ions by means of the standard addition method of differential spectrophotometry. The chromogenic reaction of Mg^2＋ with Erichrome black T was carried out in the NHε-NH4Cl buffer solution with a pH value of 10.5.The maximum absorption wavelength was 530 nm. The Beer＇s law was obeyed in the range of Mg^2＋ concentration equating to 0.06 -0.5μg/mL, and the molar absorptivity was 2.23×10^4L·mol^-1·cm^-1. This method not only could be applied to determinate the highly concentrated materials, but also could counterbalance the background disturbance. The time for determination is short, and the operation is simple. Moreover, the reagents as well as the instrument are the conventional ones with very cheap price.

关 键 词：差示分光光度法中的标准加入法 铬黑T EGTA 水泥 氧化镁 

分 类 号：O614.22[理学—无机化学]