Dispersive Liquid-liquid Micro-extraction Atomic Absorption Spectrometry In The Application And Research In The Determination Of Trace Heavy Metals

Dispersive liquid-liquid micro-extraction?Dispersive liquid liquid micro-extraction, DLLME? may solve the problem that natural samples can not directly be measured, and widely be used in many fields. This method is high efficiency, small organic drug consumption, operation of steps and simpler, less experimental conditions require many features such as simple. At present, has been successfully applied to the analysis of trace substances in water samples.Graphite furnace atomic absorption spectrophotometry?GFAAS?measurement range wide, high sensitivity and high selectivity of a detection means, can meet the needs of the determination of trace metal analysis. This paper will combine DLLME with GFAAS determination of metal elements in environmental water samples,and fruit juice. The research content is summarized as follows:1. Ammonium pyrrolidine dithiocarbamate?APDC? as the chelating agent, carbon tetrachloride?CCl₄? as the extraction solvent, methanol?CH3OH? as the dispersant. To explore the kind and amount of the extraction solvent and amount, concentration of the chelating agent and dispersant, p H of solution, and many other elements of determination cadmium?Cd? in environmental water samples, and the effects of extraction. In well optimized experimental conditions, testing condition is: water p H=3, solvent extraction of carbon tetrachloride?CCl₄? 40?L, dispersant of methanol?CH3OH? 0.5m L, chelating agent?APDC? concentration is0.012 g/L Under this condition, the determination of Cd LOD is 0.029ng/L, linear range of 1.00²5.00 ng/L, concentration of 10.00 ng/L Cd standard solution determination of 10 times the RSD was 3.5 %. The method used in the analysis of trace Cd in tap water, river water and mineral water, the standard addition recovery: 95.6¹03. %, the detection result is satisfactory.2. With dithizone(C₁₃H₁₂N₄S) as the chelating reagent, carbon tetrachloride?CCl₄? as the extraction solvent, methanol?CH3OH? as the dispersant. To explore the extraction solvent and the kinds of dispersants and the effects such as amount, chelating agent concentration, solution p H on the effect of the extraction effect of zinc in the fruit juice, under the optimized experimental conditions for determination of zinc in fruit juice elements. sample p H=3,chelating agent dithizone concentration was 1.5%, the solvent extraction of carbon tetrachloride of 50 ?l, 0.5 m L dispersant methanol. Under this condition, the determination of zinc in the LOD is 5.1 ng/L, linear range of 0²0.00 g/L concentration of 10.00 g/Lzinc liquid standard determination of 10 times the RSD was 2.6%.This method is used in apple juice, pear juice and orange juice in the analysis of trace concentrations of zinc, standard addition recovery rate is 98.0¹03%, obtained satisfactory results.3. With 1,3,5-Triazine-2, 4, 6-trithiol trisodium salt?TMT? as the chelating agent, carbon tetrachloride?CCl₄? as the extraction solvent, methanol?CH3OH? as dispersant solvent. To explore the kinds of extraction solvent and dispersant, the amount of extraction solvent and dispersant, chelating agent concentration,solution p H and many other elements of determation Cd, Pb, Cr in environmental water samples, and the effects of extraction.detection in environmental water samples is established a new method of Cd, Pb, Cr. the optimal conditions were: p H=3⁴,chelating agent TMT concentration is 0.05 mol/L, 40?L CCl₄ extraction solvent, dispersant of methanol 0.5 m L.Under this condition, Cd, Pb, Cr LOD were 0.00040 ng/m L, 0.021 ng/m L, 0.017ng/m L, linear range were 0.005⁰.02 ng/m L, 0.2¹5.0 ng/m L,15.0¹5.0 ng/m L, the concentration 10.00 ng/m L Cd, Pb, Cr standard liquid were determined 10 times the RSD is 3.7 %, 3.0 % and 2.7 %respectively, enrichment factor, 95, 68 and 100 respectively. The technology used in tap water, mineral water and lake water samples in the trace Cd, Pb, Cr analysis, test results satisfy with people.