碱性提取-电感耦合等离子体发射光谱法测定铬渣场土壤高含量六价铬OA

The hexavalent chromium Cr(Ⅵ)content in chromium slag field soils typically ranges from tens to thousands of mg/kg,far exceeding the background values of ordinary soils and exhibiting complex matrices.Existing methods for determining high-level Cr(Ⅵ)in such contaminated sites are susceptible to matrix interferences.This study introduces a synergistic extraction method based on the industrial standard HJ 1082-2019 alkaline extraction solution,enhanced by the addition of EDTA chelating agent and Triton X-100 surfactant.This method improves extraction efficiency and suppresses Cr(Ⅲ)oxidation through dual mechanisms of chemical chelation and physical dispersion.Optimal extraction conditions,determined via orthogonal experiments,include:12 mL alkaline extraction solution,90℃extraction temperature,80 min extraction time,3 mL Triton X-100,12 mL EDTA,and a solid-to-liquid ratio of 1∶54(g:mL).Under the optimal extraction conditions,the recovery rate of Cr(Ⅵ)in soil reached 96.8%,and the number of extractions was reduced from 6 times in the HJ 1082-2019 standard method to 2 times in this method.Cr(Ⅵ)quantification was performed using inductively coupled plasma-optical emission spectrometry(ICP-OES),with high-salt matrix interferences mitigated by adding 2.0 g of 001×7 strong acid cation exchange resin.The method exhibited excellent linearity(0-8.00 mg/L),a detection limit of 0.30 mg/kg,a quantification limit of 1.01 mg/kg,and an upper detection limit of 3200 mg/kg.Validation using certified reference materials[GBW(E)070255,RMH-A043]and two high-content Cr(Ⅵ)self-prepared samples demonstrated close agreement between measured and certified values(relative errors from-2.87%to-0.69%)and low relative standard deviations(RSD<5.00%).Compared to flame atomic absorption spectrometry,this method offers superior matrix interference resistance and broader applicability,and has been successfully applied to Cr(Ⅵ)determination in soils from a chromium slag field in North China.The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202503170047.