Application Of Dispersive Liquid-liquid Microextraction In The Analysis Of Heavy Metals

Nowadays, a great deal of heavy metals were discharged into soil, rivers and oceans by all kinds of ways due to the irrational metal exploiting, smelting and processing, and which posed a great threat on the soil and aquatic environment. The pollution of heavy metals has absorbed more and mort attention because of the fact that heavy metals can not be degraded in the environment and which can be accumulated by the food chain and eventually put a serious damage on human health. Hence, it is very important to develop new monitoring techniques for heavy metals, which are of great value to detect heavy and control metal pollution at real time for the life safety and environmental protection.Dispersive liquid phase microextraction is a new sample preparation technique recently, which has overcome many shortcomings of traditional liquid phase microextraction methods. It incorporates the extraction, purification, and preconcentration. It is adapted to the development requirement of the modern analytical techniques. Dispersive liquid phase microextraction is a new extraction pattern, and which has many advantages such as rapidness, simplicity, easy to operate, and high sensitivity. The goal of this thesis is to develop new determination methods for trace lead and cadmium in environments with dispersive liquid phase microextraction in combination with atomic fluorescence detection.A review was presented on the definition, harms, sources, treatment and adopted measurements for the pollution of heavy metals at home and abroad in recent years. Further, new methods for the trace determination of lead and cadmium in environmental water samples were established with dispersive liquid phase microextraction in combination with atomic fluorescence detection, respectively. The parameters that would affect the enrichment performance were investigated in detail such as the volume of extraction solvent, the sample pH, kind and amount of chelating agent, extraction time and centrifugation time. Under the optimal conditions, the detection limit of lead and cadmium were 0.95 and 19.4 ngL^-1, and precisions of lead and cadmium were 2.12% and 1.93%., respectively. The developed methods were satisfactory due to their high sensitivity and good stability for the real water samples.