Study On The Application Of Ultra Trace Analysis By Magnetic Graphene Oxide Coupled Atomic Fluorescence Spectrometry

Heavy metal contaminants in water can result in various undesirable consequence.Various methods have been proposed to remove the contaminants from water.MGO is regarded as the most promising absorbent to adsorb various heavy metal ions.Due to its large theoretical specific surface area,surface,hydrophilicity,high negative charge density and easily synthesized.The simultaneous isolation and enrichment of analytes,and facilitates separation of the sorbent with analytes adsorbed on the surface by using an external magnetic field.AFS has advantage of high sensitivity and low detection limit for the low concentration metal hydride.This paper aims to the preparation of MGO nanoparticles materials.Using MSPE combined with AFS to separation and preconcentration Pb（Ⅱ）and Cd（Ⅱ）which in the water.Research contents were as following:1.Preparation of MGO nanoparticles.The material is used for separation and preconcentration Pb（Ⅱ）and Cd（Ⅱ）which in the water.Fe₃O₄-GO nanoparticles were characterized with FT-IR.And a series of parameters affecting MSPE was optimized systematically.Under the optimal experimental conditions,the limits of detection（3 s,n=11,）of Pb（Ⅱ）and Cd（Ⅱ）were 0.0750 ng?mL^-1,0.0500 ng?mL^-1,respectively.The working range were 0.150-12.0 ng?mL^-1,0.0800-5.00 ng?mL^-1,respectively.The intra-day relative standard deviations（RSD,n=7,）were 3.00 % and 4.24 %,respectively.The recoveries were observed in the range of 93.0 %-96.8 %,91.3 %-96.7 %,respectively.2.GO and Fe₃O₄ magnetic nanoparticles were used as original materials to prepare MGO.A new preconcentration-seperation and analysis method was developed to detect Pb（Ⅱ）and Cd（Ⅱ）in water,based on MGO coupled with AFS.Characterized by FT-IR.Under the optimized condition,.The limits of detection（LOD）of Pb（Ⅱ）and Cd（Ⅱ）were 0.0410 ng?mL^-1,0.0270 ng?m L-1,respectively.Working range were 0.100-14.0 ng?mL^-1,0.0500-5.00 ng?mL^-1,respectively.The intra-day relative standard deviations（RSD,n=7）were 2.34 %,3.48 %,respectively.The results indicated that the method was accurate and reliable,and was successfully applied for the determination of Pb（Ⅱ）and Cd（Ⅱ）.The recoveries were observed in the range of 91.8 %-101 %,93.3 %-102 %,respectively.3.Fe₃O₄@SiO₂@chitosan@GO nanoparticle composites were prepared by further modification of Chitosan,Pb（Ⅱ）and Cd（Ⅱ）were detected by hydride generation atomic fluorescence spectrometry（AFS）.FT-IR was also used to characterize the synthesis of materials.Based on the optimization of the factors affecting the enrichment and separation,the properties of the material were studied,conclusions are as follows: the limits of detection（3 s,n=11,）of Pb（Ⅱ）and Cd（Ⅱ）were 0.0630 ng?mL^-1,0.0527 ng?m L-1,respectively.The working range were 0.150-20.0 ng?mL^-1and 0.120-12.0 ng?mL^-1,respectively.The intra-day relative standard deviations（RSD,n=7,）were 2.72 %,3.44 %,respectively.The recoveries were observed in the range of 91.1 %-105 %,92.3 %-104 %,respectively.