3,5-二溴-PADAP分光光度法测定微量NO_2^-离子的研究

Spectrophotometric Determination of NO - 2 with 2 (3,5 Dibromo 2 Pyridylazo) 5 Diethylaminopheol and SCN -

系统研究了３，５－二溴－ＰＡＤＡＰ在酸性介质中质子化后与ＮＯ－２和ＳＣＮ－形成三元离子缔合物的最佳条件。提出了测定微量ＮＯ－２的分光光度新方法，表观摩尔吸光系数ε６３０＝１．２×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，缔合物组成比为ｎ（３，５－二溴－ＰＡＤＡＰ）∶ｎ（ＮＯ－２）∶ｎ（ＳＣＮ－）＝１∶１∶１。本法应用环境水体中微量ＮＯ－２的测定，与经典方法对照结果吻合。

The ion association system of protonated 2 (3,5 dibromo 2 pyridylazo) 5 diethyl aminophenol、SCN - and NO - 2 in a medium of H 2SO 4 was studied.They form a grey and green ion association complex of low ligand number [3,5 2Br PADAP H 2+ 2]·NO - 2·SCN -.The molar absorptivity is 1.2×10 4L·mol -1 ·cm -1 and the composition ratio of n (3,5 2Br (PADAP))∶ n (SCN -)∶ n (NO - 2) is 1∶1∶1 .This method can be used for determining trace NO - 2 in waters.