Low-density Solvent Based Dispersive Liquid Liquid Microextraction Combined With Graphite Furnace Atomic Absorption Spectrometry For The Determination Of Trace Heavy Metals In Water

Dispersive liquid liquid microextraction(DLLME)is a new sample pretreatment technique with the advantages of simple operation and high extraction efficiency.DLLME has achieved rapid development in new extractants,dispersion methods and phase separation methods,and has a wide range of application in trace analysis chemistry.In this paper,it is based on low density solvent,and aimed at establishing a new rapid and efficient dispersive liquid liquid microextraction method to expand the application of DLLME in trace heavy metals analysis in water.The major contents were summarized as follows.(1)1-Octanol,as a low density solvent,was used as extractant to establish a dispersive liquid liquid microextraction method combined with graphite furnace atomic absorption spectrometry(LDS-DLLME-GFAAS).The method was applied to the determination of trace Pb(?)and Cd(?)in domestic water and drinking water.The experimental parameters such as the type and volume of extractant,the type and volume of dispersant,the pH,the concentration of DDTC and the extraction time were investigated experimentally.Under the optimal experimental conditions,the detection limits of Pb(?)and Cd(?)were 0.15 ?g/L and 0.03 ?g/L,respectively,and the relative standard deviations were less than 7.4%.The relative recoveries of bottled waters,tap water and South Lake water were 58%-117%.(2)1-Octanol,as a low density solvent,was used as extractant to establish a dispersive liquid liquid microextraction method combined with graphite furnace atomic absorption spectrometry(LDS-DLLME-GFAAS).The method was applied to the determination of trace Cr(?)and Cr(?)in environmental water samples.The experimental parameters such as the type and volume of extractant,the type and volume of dispersant,the pH,the concentration of APDC and the extraction time were investigated experimentally.Under the optimal conditions,the detection limit of Cr(?)was 0.049 ?g/L and the relative standard deviation was less than 4.5%.The spiked recoveries of South Lake water,Yangtze River water and tap water were 76%-118%.(3)1-Octanol,as a low density solvent,was used as extractant to establish a one-step displacement dispersive liquid liquid microextraction method combined with graphite furnace atomic absorption spectrometry(LDS-D-DLLME-GFAAS).The method was applied to the determination of trace Ag(?)in environmental water samples.In the experiment,Ag(?)was used to replace Cu(?)-DDTC to achieve high selective separation and detection of Ag(?)in water samples,which greatly reduced the interference of coexisting ions and had strong anti-matrix interference ability.The detection limit of this method for Ag(?)was 0.056 ?g/L,with a relative standard deviation of less than 4.93%.The spiked recoveries of South Lake water and tap water were 88%-102%.