干扰校正-电感耦合等离子体原子发射光谱法测定钢铁中锌
Determination of zinc in steel by inductively coupled plasma atomic emission spectrometry with interference correction
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摘要: 在钢铁中添加锌元素可提升强度与耐蚀性,但过量添加会劣化材料性能,因此准确测定锌含量对生产高品质钢铁至关重要。本文建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定钢铁中锌的方法,筛选出对锌干扰显著的元素,分析其在不同基体及称样量下对锌的影响,通过建立数学校正模型对目标谱线进行干扰校正,并采用多类型标准物质/样品验证方法。结果表明:铜对Zn 202.548 nm、镍对Zn 213.856 nm干扰显著;铜、镍在不同基体中对锌的干扰效应稳定;不同称样量下干扰贡献显著,测定误差与称样量呈相关性;经校正后,采用Zn 202.548 nm和Zn 213.856 nm为锌的分析谱线测定6种样品的准确度显著提升;其中Zn 206.200 nm受共存元素干扰最小,可作为锌的优选分析谱线。方法中锌的测定范围为0.001 0%~0.10%(质量分数,下同),校准曲线线性相关系数不小于0.999 8;方法检出限为0.000 14%,定量限为0.000 48%。按照实验方法测定标准物质/样品中锌,结果的相对标准偏差(RSD, n=11)为2.2%~5.7%,结果与认定值/标准值相吻合;本方法与电感耦合等离子体质谱法(ICP-MS)的比对结果高度一致。Abstract: The addition of zinc into steel can enhance strength and corrosion resistance. However, excessive zinc addition will compromise material properties. Therefore, accurate determination of zinc content is crucial for producing high-quality steel alloys. In this study, a method for the determination of zinc in steel by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. Elements causing significant spectral interference with zinc were identified, and their influences were analyzed under varying matrix compositions and sample masses. A mathematical correction model was developed for interference correction of the target spectral lines. The method was validated using various certified reference materials (CRMs) and samples. The results demonstrated that copper caused significant interference with Zn 202.548 nm, while nickel interfered significantly with Zn 213.856 nm. The interference effects of copper and nickel on zinc were stable across different matrices. The interference contribution varied significantly with sample mass, and the determination error correlated with it. After correction, the determination accuracy for six samples was significantly improved using Zn 202.548 nm and Zn 213.856 nm as analytical lines. The Zn 206.200 nm line experienced the minimum interference from coexisting elements and could be selected as the optimal analytical line. The determination range of this method was 0.001 0%-0.10% (mass fraction, the same below), with a linear correlation coefficient of the calibration curve not less than 0.999 8. The limit of detection was 0.000 14%, and the limit of quantification was 0.000 48%. Zinc contents in CRMs/samples were determined using the experimental method, yielding relative standard deviations (RSD, n=11) between 2.2% and 5.7%. The measured results agreed with certified/reference values. Comparison tests showed good agreement between the results of this method and those obtained by inductively coupled plasma mass spectrometry (ICP-MS).
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