›› 2016, Vol. 28 ›› Issue (12): 2123-2129.DOI: 10.3969/j.issn.1004-1524.2016.12.23

• Biosystems Engineering • Previous Articles    

Application of uniform design method in optimizing PXRF determination methods of heavy metals in soil

YANG Gui-lan1, SHANG Zhao-cong1,2, LI Liang-jun1, NI Xiao-fang1,2,*, ZHANG Ming-hong1,2   

  1. 1. Shanghai Research Institute of Chemical Industry, Shanghai 200062, China;
    2. Shanghai TECH. Chemical Industry Testing Co., Ltd, Shanghai 200062, China
  • Received:2016-02-16 Online:2016-12-15 Published:2017-01-05

Abstract: Total concentrations of Cr, Cu, Zn, As and Pb in farm land soil from Yangtze River Delta region were determined by portable X-ray fluorescence spectroscopy (PXRF). A regression model between the overall average of relative standard deviation (RSD) and relevant factors was established using uniform design and quadratic polynomial stepwise regression method. It was shown that the optimal detection conditions were obtained as air dried sample, 0.125 mm particle size, 3 MPa sampling pressure and 115 s detection time. The relative error between the overall average of RSD (the average of 5 elements' relative standard deviation) for experimental values and the overall average of RSD for predicted values in regression model verification test were less than 5%, indicating a good predictive ability of the regression model. Under such optimal detection conditions, the detection limits of PXRF for Cr, Cu, Zn, As, and Pb were 15.0, 4.12, 3.22, 2.22 and 3.14 mg·kg-1, respectively. For total concentrations of Cr, Cu, Zn, As and Pb in 33 soil samples determined by PXRF and ICP-OES, the linear regression models' coefficients R2 were all greater than 0.97, and the relative error between model predicted values and ICP-OES measured value of 7 unknown samples were less than 10%. The results showed that under the optimal detection conditions, test data by PXRF reached a quantitative analysis level through linear regression model calibration.

Key words: PXRF, soil, heavy metals, detection conditions, uniform design experimentation

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