论文部分内容阅读
2-〔5-溴2-吡啶偶氮〕-5-二乙氨基酚(5-Br-PADAP)用于萃取光度法测定微量金属已有报道,但要使用有毒害的有机溶剂,操作过程亦繁琐冗长。笔者研究了在非离子表面活性剂聚乙二醇辛基苯基醚(OP)存在下的镉(Ⅱ)与5-Br-PADAP的显色特性,配合物的最大吸收在560nm,表观摩尔吸光系数ε_(560)=1.16×10~5 l·mol~(-1)·cm~(-1),0—19μgCd/25ml范围符合比尔定律。用摩尔比法和等摩尔连续变化法测定配合物组成比为Cd(Ⅱ):R=1:2(金属:试剂)。将拟定的方法用于水、土等样品中微量镉的分析,获得满意的结果。 (一)主要试剂和仪器
2- (5-Bromo-2-pyridylazo) -5-diethylaminophenol (5-Br-PADAP) has been reported for the determination of trace metals by extraction spectrophotometry. However, toxic organic solvents should be used. Tedious lengthy. The author studied the color development of cadmium (Ⅱ) and 5-Br-PADAP in the presence of non-ionic surfactant polyethylene glycol octylphenyl ether (OP). The maximum absorption of the complex at 560nm, apparent molar The absorbency coefficient ε 560 was 1.16 × 10 5 mol·L -1 cm -1, and Beer’s law was obeyed in the range of 0-19 μg Cd / 25 ml. The composition ratio of Cd (Ⅱ): R = 1: 2 (metal: reagent) was determined by molar ratio method and equimolar continuous change method. The proposed method is applied to the analysis of trace cadmium in water and soil samples to obtain satisfactory results. (A) of the major reagents and equipment