Rapid Determination of (Metalloid) Metal Elements in Soil by Portable X-Ray Fluorescence Spectrometer Based on Hyperbolic Curved Crystal Technology

In order to address the shortcomings of limited types of detection elements and high detection limits of some elements in the detection of (metalloid) metal elements in the soil by portable X-ray fluorescence spectrometers, heavy (metalloid) metal elements, metal nutrient elements, and heavy (metalloid) metal elements with mining values included in GB 15618-2018, GB 36600-2018 and the Third National Soil Census Work Plan issued by the Ministry of Agriculture and Rural Affairs were selected as the target elements, and the comprehensive investigation was conducted on the feasibility of the title method's application (detection limit, precision, and accuracy). After drying, grinding, and compaction, the soil samples were analyzed using a portable X-ray fluorescence heavy metal analyzer equipped with the hyperbolic curved crystal, target elements in which were quantified using the fast fundamental parameters(Fast FP). It was shown that detection limits of major target elements (such as Cd, Hg, As, Cu, Sb, Tl, Mo, Sn, Se, Cs, etc.) were in the range of 0.2-3 mg·kg^-1, which were basically lower than the environmental background values or the limits required by the above standards (excluding Hg and Se). The proposed method was applied to the analysis of 3 sediment composition analysis reference materials and 2 soil composition analysis reference materials. Except for elements with determined values below the lower limit of determination and Tl, Mg elements, RSDs (n=7) of the other major target elements in the reference materials were basically less than 20%, and absolute values of relative errors were basically less than 35%. The RSD and relative error of the elements of Cu, Pb, Cr, Zn and Ni (the basic item elements) met or were close to the allowable error requirements for the precision and accuracy of indoor parallel double sample determination in HJ/T 166-2004. The above method was applied to the analysis of 5 actual soil samples, and the results obtained were basically consistent with those of the standard analysis methods. The proposed method had the characteristics of quickness, high accuracy, good reproducibility, and abundant qualitative and quantitative elements, making it suitable for on-site determination of (metalloid) metal elements in soil in multiple occasions.