氨电极法测定部分水解聚丙烯酰胺浓度

Determination of Partially Hydrolyzed Polyacrylamide with NH_3-Selective Electrode

经敏化的氨选择气敏电极（NH3-ISE）由于其测定的高选择性和精密度，较适用于石油开产过程中对聚合物溢流液中部分水解聚丙烯酰胺（PHPA）浓度的动态监测。试样按凯氏定氮法进行消化处理。在硫酸的作用下，PHPA分子中的酰胺基转化为NH4^＋离子，于试液中加入氢氧化钠溶液调节其pH至11左右，使NH4^＋转化为NH3后用NH3-ISE进行检测。适宜的PHPA的测定范围为6．00-45.00mg·L^-1；在此范围内，测定值的相对标准偏差均小于4.1％，几乎所有无机离子对测定无干扰或干扰甚微，但挥发性胺有明显干扰。此法也能用于去离子水及矿泉水的分析。

It was found that the sensibilized NH3-selective electrode （NH3-ISE） was suitable to be used in the dynamic monitoring of the concentration of partially hydrolyzed polyacrylamide （PHPA） in the process of petroluem recovering for its high sdectivity and precision. The sample was digested as in the Kjddahl method for determination of nitrogen, and amide group in the PHPA molecule was transformed into NH4^＋ ion by the action of sulfuric acid. Sodium hydroxide solution was added to the sample solution to adjust the pH of the solution to around 11, and the NH4^＋ was converted to NH3 and detected by the NH3-ISE. The optimum range of FHPA to be determined by this method was found as from 6.00--45. 00 mg·L^-1 , where the RSD＇s found were less than 4. 1%. Almost all of the inorganic ions do not interfere or only interfere slightly in this determination. But significant interferences were observed by volatile amines. The proposed method was also suitable to be used in the analysis of deionized water and mineral water.