4-(对-甲氧基苯氨基重氮基)-4'-硝基偶氮苯的合成及其与汞(Ⅱ)的显色反应

Synthesis of 4-(p-methoxyphenyaminodiazo)-4'-nitroazobenzene and its colour reaction with mercury

合成了新显色剂4-（对甲氧基苯氨基重氮基）-4＇-硝基偶氮苯（PMADNA），并研究了该试剂在TritonX—100存在下与汞的显色反应。结果表明，在pH10．5的Na2B6O2-NaOH缓冲介质中，Hg㈣与试剂形成稳定的1：2红色络合物，最大吸收波长位于576nm，表观摩尔吸光系数为1．25×10^5L·mol^-1·cm^-1汞的质量浓度在0～0．8μg／mL范围内服从比尔定律，用酒石酸钠-焦磷酸钠-氟化钠作混合掩蔽剂，可以提高Fe3＋，Ni2＋，Cu2＋，Cd2＋的允许量。方法用于废水中微量汞的直接测定，相对标准偏差为1．8％～2．2％，回收率为99．1％～103．8％。

A new reagent 4-（p-methoxyphenyaminodiazo）-4＇-nitroazobenzene （PMADNA） was synthesized and its colour reaction with mercury was studied. In the presence of Tirton X-100, Hg（Ⅱ） reacts with PMADNA to form a red complex with molar ratio of 1 ： 2 in the medium of borax-NaOH buffer of pH 10.5. The maximum absorption wavelength is located at 576 nm and the molar absorptivity of the color reaction is 1.25×10^5L·mol^-1·cm^-1. Beer＇s law is obeyed in the range of 0--0.8 μg/mL for mercury（Ⅱ）. The allowance amounts of Fe3＋ , Ni2＋ , Cu2＋ , Cd2＋ are enlarged using sodium tartratesodium pyrophosphate-sodium fluoride as masking rergent. The method has been directly applied to the determination of mercury（liD in waste water with RSD of 1.8 %--2.2 % and recovery of 99.1% -- 103.8%.