DEPAQ分光光度法测定茶叶中微量锰

Spectrophotometric Determination of Microamounts of Manganese in Tea with DEPAQ

本文研究了５－（４－二乙氨基苯偶氮）－８－羟基喹啉（ＤＥＰＡＱ）与锰（Ⅱ）的显色反应。在非离子型表面活性剂ＴｒｉｔｏｎＸ－１００存在下，ｐＨ８．５的缓冲介质中，锰（Ⅱ）与ＤＥＰＡＱ形成１：２的红色配合物，最大吸收波长为５３０ｎｍ，表观摩尔吸光系数ε＝７．３×１０４Ｌ．ｍｏｌ－１．ｃｍ－１．锰量在０～２０μｇ／２５ｍＬ范围符合比尔定律。试验了常见阴阳离子的干扰情况。本法用于茶叶中微量锰的测定，取得了令人满意的结果。

The color reaction of manganese (Ⅱ) with 5 - (4 - diethylaminophenylazo ) - 8- hy droxyquinoline (DEPAQ) is studied. In the presence of Triton X-100 and pH8. 5 buffer solution,Mn(Ⅱ) reacts with DEPAQ to form a 1: 2 red complex. The complex exhibits a maximum absorption at 530 nm with an apparent molar absorptivity of 7. 3 × 104 L· mol-1. cm-1. Beer'slaw is obeyed in the range of 0-20 μg Mn(Ⅱ)/25 ml. The interference of common ions is also investigated. The proposed method is applied to determine of microamounts of manganese in tea with satisfactory results.