Application Of Novel Dispersive Liquid-Liquid Microextraction For Trace Metal Elements Analysis In Complex Samples

With the development of industrial and technological,it is crucially important to monitor the trace element in environment samples. Due to the requirments of enironmental analytical to promote the further development of trace ng/mL or even ultra trace ng/L analysis. Although atomic absorption spectrometry (AAS) with high sensitivity is powerful analytical tool for determining trace elements in environmental samples, in order to achieve accurate and reliable results, an efficient separation and preconcentration procedures are still necessary.In recent years, dispersive liquid-liquid microextraction(DLLME) is a novel method of preconcentration, which overcomes the deficiencies of traditional pretreatment technology, with high extraction effeciency, high enrichment factor, simple operation, safe, economical, low toxicity, environmentally friendly compared with traditional extraction methods.Therefore, it has potential applications in the separation and preconcentration of trace metal ion fields. In order to reduce the interference of coexisting ions, based on DLLME a high selectivity in complex matrices displacement extraction technique, anti-interference ability of method is very to the degree of improvement. Supramolecular solvent(SUPRASs) extraction and UASEME use non-toxic green solvents to replace organic solvents, to some extent, the green extraction requirements.Atomic absorption spectrometry with high sensitivity, high selectivity, the determination of elements is in a wide range, high precision, less injection, and rapidity. While DLLME associated with GFAAS can significantly reduce the detection limit (LOD), satisfy the requirements of trace/ultra-trace elemental analysis.In this study, novel DLLME with GFAAS was established for determining trace metal ions, and applied to the real samples with satisfactory results.The main research contents are summarized as follows:1.The method based on displacement dispersive liquid-liquid microextraction (D-DLLME) preconcentration and GFAAS detection was successfully proposed for the determination of trace lead in water samples. In the proposed approach, DDTC was used as a complexing agent, CH3OH and CCl4were selected as dispersive and extraction solvents. The various parameters that affect the efficiency of D-DLLME were optimized. The method can be successfully applied to the separation, preconcentration and determination of Pb in water samples.2. A new selective one-step D-DLLME method was developed for determination of trace silver in complicated samples by GFAAS. In the proposed approach, DDTC was used as a chelating agent, CH3OH and CCl4were selected as dispersive and extraction solvents. The various parameters that affect the efficiency of One-step D-DLLME were optimized. The method can be successfully applied to the separation, preconcentration and determination of Ag in environmental and geological samples with satisfactory result.3. A novel selective ultrasound-assisted surfactant-enhanced emulsification one-step displacement dispersive liquid-liquid microextraction (UASE-OSD-DLLME) method was developed for determination of trace silver in complicated samples by GFAAS. In this proposed procedure, Sodium DodecylSulfate was used as emulsifier, and chlorobenzene(C6H5Cl) was used as extraction solvent without using any organic dispersive solvent, Ni-DDTC complex instead of DDTC was used to achieve one-step extraction. The various parameters that affect the efficiency of UASE-OSD-DLLME were optimized.The method can be successfully applied to the separation, preconcentration and determination of Ag in environmental and geological samples.4. A method of supramolecular-based dispersive liquid-liquid microextraction (SM-DLLME) was developed as a novel and sensitive approach for determination of trace lead in complicated samples by GFAAS. The SM-DLLME behavior of lead using DDTC as a chelating agent, decanoic acid and tetrahydrofuran (THF) were selected as extraction and dispersive solvents.The lead ions are micro-extracted with coacervates composed of reverse micelles made from decanoic acid and dispersive in THF water mixtures. The various parameters that affect the efficiency of SM-DLLME were optimized. The precision and accuracy were satisfactory. The method can be successfully applied to the separation, preconcentration and determination of Pb in water samples.