A novel method for determination of available Cu(Ⅱ)in soil by integrating Diffusive Gradients in Thin-films and portable X-ray fluorescence spectrometry
A novel method for determination of available Cu(Ⅱ)in soil by integrating Diffusive Gradients in Thin-films and portable X-ray fluorescence spectrometry
Soil copper(Cu)pollution has been an increasingly serious concern in all aspects of life.The available Cu(Ⅱ)with exceedingly high bioavailability might pose a threat to human health and surrounding environment.However,the existing methods for determination of available Cu(Ⅱ)speciation are cumbersome and inefficient.The prestnt study aimed to develop a novel method for determination of available Cu(Ⅱ)speciation by integrating both Diffusive Gradients in Thin-films(DGT)and portable X-ray fluorescence spectrometry(pXRF).Available Cu(Ⅱ)in soils was extracted by Chelex DGT,and determined by traditional Atomic absorption spectroscopy(AAS)after acid elution and portable X-ray fluorescence spectrometry(pXRF),respectively.The available Cu(Ⅱ)determined by AAS was set as the standard to measure the accuracy of the value directly determined by pXRF in air dried DGT binding gel.Initially,the calibration curves of pXRF signals and traditional HNO3 elution method for available Cu(Ⅱ)accumulated in DGT binding gels was established in standard solution system.Furthermore,the interferences of lead(Pb),nickel(Ni),cadmium(Cd),and zinc(Zn)with available Cu(Ⅱ)during determination by pXRF in multi metal ion coexisting system was examined.Finally,the pXRF was used to determine the available Cu(Ⅱ)in soils extracted with DGT.The results showed that:There was a strong linear relationship between available Cu(Ⅱ)accumulated in DGT Chelex binding gel determined by pXRF directly and that determined by the traditional elution method with AAS in the laboratory(R2=0.9963);pXRF can accurately measure as low as 1.14 pmol L-1(0.0724 mg·L-1)of available Cu(Ⅱ)extracted by DGT;The coexisting Pb(Ⅱ),Cd(Ⅱ),Ni(Ⅱ),and Zn(Ⅱ)did not interfere with the pXRF determination of available Cu(Ⅱ)extracted by DGT;The available Cu(Ⅱ)accumulated in DGT binding gel extracted from soils measured by pXRF directly was consistent with that determined by traditional elution method.Therefore,this new method for determination of available Cu(Ⅱ)in soil by combining DGT and pXRF could meet the requirements of the accuracy and precision,which supported the direct determination of available heavy metals in the field.The application and promotion of this method can greatly save laboratory analysis time,manpower,material resources,and other costs.
维普
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