5-Br-PADAP Coprecipitation System Mensurate Trace Amounts Of Metal In Environmental Samples By Atomic Absorption Spectrometry

With the improvement of living conditions and the increase of safety awareness, the determination of trace metals in the samples is often required to achieve high sensitivity of ppb level currently. However, some instruments with high sensitivity don’t satisfy the requirements of detection in the actual work today. And they are so expensive that many laboratories cannot afford them. By using the separation and enrichment, ordinary instruments can enhance the selectivity and sensitivity. In a variety of enrichment and separation ways, the coprecipitation method has the advantages of simple and rapid operation, high enrichment factor. And coprecipitation can also be used in the detection and isolation of a variety of elements at the same time. In conclusion, this method becomes the most effective one.This paper mainly focuses on the determination of trace metal ion such as zinc, chrome, copper, cadmium in environment by using Mn-5-Br-PADAP, Zn-5-Br-PADAP as coprecipitant firstly. This experiment chooses appropriate carrier elements, suitable amount of elements and reagents, compatible standing time of the precipitate and adaptive pH, etc.This paper studies on the following four systems:1. Using Mn-5-Br-PADAP as coprecipitant to measure the amounts of trace zinc in water samples. When Zinc’s concentration was 1.0mg/L, the precision of the determination was 0.67%(n=13). Meanwhile, the detection limit (DL)was 0.24μg/L. The method has been applied to detect zinc in water samples, the recoveries of zinc ranging from 95.2% to 104.7%.The amount of zinc in underground water is 8.8×10-3mg/L, and the amount of zinc in the tap water is 0.039mg/L.2. This paper measured the content of chrome in apple peel by running Zn-5-Br-PADAP as coprecipitant. When the concentration of chrome was 1.0mg/L, the precision of the method was 1.60% (n=11).The detection limit (DL)was 17.4μg/L. The amount of chrome in apple peel is 3.09mg/kg.3. Measuring the amounts of copper in tobacco samples by Zn-5-Br-PADAP as coprecipitant. When the concentration of copper was 2.0mg/L, the precision of the determination was 1.15%(n=11). Simultaneously, the detection limit (DL)was 2.73μg/L. The amount of copper in tobacco is 35.5μg/g.4. The method based on coprecipitant Mn-5-Br-PADAP to survey the amounts of cadmium in dried scallop and dried shrimps samples. When the concentration of cadmium was 1.0mg/L, the precision of the determination was 0.73%(n=11). Moreover, the detection limit (DL)was 4.27μg/L. The amount of cadmium in dried scallop is 1.85mg/kg, and the amount of cadmium in dried shrimps is 1.74 mg/kg.The effect of matrix can be overcome by the method. This method is simple, rapid and has low detection limit. It is an effective way to determinate metal ions in environmental sample with flame atomic absorption spectrometry.