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稀土元素用于农业能使作物增产,为配合铈对农作物的作用机理的研究,要对铈进行测定。用光度法测定合金、铸铁中的铈已有报道。我们参照文献1结合土壤具体情况,将样品经碱熔、浸提共沉淀后,用PMBP/异戊醇+环已烷萃取,在有机相中加PMBP-钒螯合剂,使三价铈氧化成四价,然后先以PH=2的盐酸反萃三价稀土,再以1％抗坏血酸和3％盐酸还原反萃取铈。将此反萃液在PH=2.2的盐酸—醋酸钠介质中,用新型显色剂—对乙酰基偶氮胂显色,在波长670毫米处ε_0=11.6×10~4此方法较简便、灵敏、稳定,满足土壤中微量铈的测定要求。
Rare earth elements used in agriculture can increase crop production, in order to meet the mechanism of cerium on crop research, to determine the cerium. The spectrophotometric determination of cerium in cast iron has been reported. We refer to the literature 1 with the specific circumstances of the soil, the sample by alkali melting, precipitation coprecipitation, with PMBP / isoamyl alcohol + cyclohexane extraction, the organic phase plus PMBP-vanadium chelating agent, the oxidation of trivalent cerium into Tetravalent, and then stripping trivalent rare earth with hydrochloric acid of PH = 2 and then cerium with 1% ascorbic acid and 3% hydrochloric acid. The stripping solution in pH = 2.2 hydrochloric acid - sodium acetate medium, with a new color reagent - acetyl arsenazo color, 670 mm wavelength ε_0 = 11.6 × 10 ~ 4 This method is relatively simple and sensitive , Stable, to meet the determination of trace cerium in soil requirements.