ICP-AES测定邻苯二甲酸氢钾-氢氧化钠作用下土壤中重金属全量及形态分析

空白土壤作为质量控制样品，采用邻苯二甲酸氢钾-氢氧化钠进行处理土壤样品为对照，用HNO₃-HF-HClO₄混酸对土壤样品进行消化，运用等离子体发射光谱仪(ICP-AES)测定了提取处理后土壤样品中Mo, Pb, As, Hg, Cr, Cd, Zn, Cu, Ni的全量以及酸可提取态、氧化物结合态、有机结合态三种化学形态的含量。获知不同pH的邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中重金属全量及形态转化作用的影响。结果表明：除Pb和Zn外，投加不同pH邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中重金属全量的消解和测定有促进作用。邻苯二甲酸氢钾-氢氧化钠缓冲溶液对土壤中Cr, Cu, Hg, Pb的酸可提取态、对土壤中As, Hg, Pb, Zn的氧化结合态、对土壤中As和Hg的有机结合态的转化有促进作用。在pH 5.8时，Cu和Hg的酸可提取态的含量最大值分别为2.180和0.632 mg·kg-1；在pH 6.2时，Pb的氧化结合态的含量最大值为27.792 mg·kg-1；在pH 6.0时，Hg的有机结合态含量最大值为4.715 mg·kg-1。

Determination of Total Mass and Morphology Analysis of Heavy Metal in Soil with Potassium Biphthalate-Sodium Hydroxide by ICP-AES

Blank soil was used as quality controlling samples, soil sample dealt by potassium biphthalate-sodium hydroxide buffer solution was used as check sample, mixed acid HNO₃-HF-HClO₄ was chosen to nitrify soil samples, and plasma emission spectrometer (ICP-AES) was used as detecting method. The authors determined the total metal mass of Mo, Pb, As, Hg, Cr, Cd, Zn, Cu and Ni in the extracted and dealt soil samples, and determined the mass of Mo, Pb, As, Hg, Cr, Cd, Zn, Cu and Ni in the three chemical morphologies, including acid extractable morphology, oxide associated morphology, and organics associated modality. The experimental results indicated that the different pH of potassium biphthalate-sodium hydroxide buffer solution had obvious influence on the total mass of heavy metal and morphology transformation. Except for metal element Pb and Zn, the addition of different pH potassium dihydrogen phosphate-sodium hydroxide buffer solution could accelerate the soil samples nitrification and the total mass determination of heavy metal in the soil samples. The potassium biphthalate-sodium hydroxide buffer solution could facilitate the acid extractable morphology of Cr, Cu, Hg and Pb, oxidation associated morphology of As, Hg, Pb and Zn and the organic associated morphology transforming of As and Hg. At pH 5.8, the maximum acid extractable morphology contents of Cu and Hg were 2.180 and 0.632 mg·kg-1,respectively；at pH 6.2，the maximal oxidation associated morphology content of Pb could achieve 27.792 mg·kg-1；at pH 6.0，the maximum organic associated morphology content of heavy metal Hg was 4.715 mg·kg-1.