氧气反应模式－电感耦合等离子体串联质谱法测定土壤中 的镉.

Rock & Mineral Analysis. 2021, Vol. 40 Issue 1, p95-102. 8p.

*Tin isotopes, *Molybdenum oxides, *Soil sampling, *Mass spectrometry, *Charge exchange, *Molybdenum, *Oxygenation (Chemistry)

BACKGROUND: When using inductively coupled plasma - mass spectrometry ( ICP - MS) to analyze soil, the zirconium hydroxide, molybdenum oxide, and tin isotopes can cause serious interference on cadmium, which makes it difficult to accurately determine cadmium in soil samples. OBJECTIVES: To develop a method for accurate determination of Cd in soil samples. METHODS: ICP - MS/MS was used, and m Cd without isobaric interference was selected as the analysis line. In MS/MS mode, the oxygen introduced into the collision reaction cell can be reacted with m Zr16 0 1 H +, m Mo 16 0 +, inducing electron transfer, dehydrogenation, oxygenation and other reactions to inhibit the overlapping interference of these polyatomic ions on m Cd. RESULTS: Oxygen flow was the key factor in this method. 0. 45mL/min oxygen flow can reduce oxide interference to less than 0. 005 μg/L when zirconium concentration was lower than 2000 μg/L and molybdenum concentration was below IOOOμg/L. The method has been verified by the national reference materials. The relative error of the measured value and recognized value of the 11 national reference materials was within ± 7%, and the relative standard deviation ( n = 12) of three soil reference materials was less than 5%. CONCLUSIONS: Triple quadrupole ICP - MS oxygen reaction mode can eliminate Zr and Mo polyatomic ion interference on Cd, and this method can be used for the determination of trace Cd in soil samples. [ABSTRACT FROM AUTHOR]

应用电感耦合等离子体质谱法（ＩＣＰ－ＭＳ）分析土壤中的镉元素时，锆的氢氧化物、钼的氧化物、锡的 同位素会对镉造成严重的干扰，导致准确测定土壤中镉的难度较大。本文采用电感耦合等离子体串接质谱 法（ＩＣＰ－ＭＳ／ＭＳ），选取无同质异位素干扰的１１１Ｃｄ为分析谱线，在ＭＳ／ＭＳ模式下碰撞反应池中通入的氧气 可以与９４Ｚｒ１６Ｏ１Ｈ＋、９５Ｍｏ１６Ｏ＋进行电子转移、去氢、加氧等反应，抑制这些多原子离子对１１１Ｃｄ的重叠干扰。结 果表明：氧气流量越大，去除多原子离子的效果越好，当氧气流量在０．４５ｍＬ／ｍｉｎ时，溶液中２０００μｇ／Ｌ以下 的锆、１０００μｇ／Ｌ以下的钼在１１１Ｃｄ处形成的多原子重叠干扰小于０．００５μｇ／Ｌ。实验在石墨消解仪中采用氢 氟酸－硝酸－高氯酸消解样品，盐酸复溶，溶液定容稀释至１０００倍测定，方法检出限（３δ）达到０．００３μｇ／ｇ； 本方法经过国家土壤一级标准物质验证，１１个国家土壤一级标准物质的测量值和认定值的相对误差在 ±７％以内，３个国家土壤一级标准物质的精密度（ＲＳＤ，ｎ＝１２）小于５％。本方法可以作为土壤样品中痕量 镉元素的分析方法。 [ABSTRACT FROM AUTHOR]

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