电感耦合等离子体质谱法测定镍铬合金中砷硒锡锑铅铋

准确测定镍铬合金中砷、硒、锡、锑、铅和铋含量,对镍铬合金的生产、应用具有重要意义。考虑到被测元素砷和硒的易挥发性质,采用10 mL盐酸-1 mL硝酸溶解镍铬合金,选用⁷⁵As、⁷⁷Se、¹²⁰Sn、¹²¹Sb、²⁰⁸Pb和²⁰⁹Bi为测量同位素,采用铑内标校正砷、硒、锡、锑的测定;铼内标校正铅、铋的测定,建立了电感耦合等离子体质谱法(ICP-MS)测定镍铬合金中砷、硒、锡、锑、铅和铋含量的方法。实验表明,在200 ℃加热蒸发样品溶液中Cl^—,将盐酸介质转化为硝酸介质,可消除多原子离子⁴⁰Ar³⁵Cl⁺、⁴⁰Ar³⁷Cl⁺对⁷⁵As、⁷⁷Se的干扰。对测定介质进行了进一步优化,确定以2%(V/V)盐酸为介质测定锡、锑、铅、铋含量;以2%(V/V)硝酸-乙醇为介质测定砷、硒含量。在优化的实验条件下,在2.00~25.00 ng/mL范围内,被测元素与相应内标元素信号强度的比值与被测元素质量浓度呈良好的线性关系,相关系数大于0.999 5。各元素的检出限为0.012~0.21 ng/mL,定量限为0.04~0.70 ng/mL。采用实验方法测定镍铬合金中砷、硒、锡、锑、铅和铋含量,测定结果与原子荧光光谱法(AFS)基本一致,相对标准偏差(n=11)为5.4%～12%,加标回收率为96%～120%。

Determination of arsenic,selenium,tin,antimony,lead and bismuth in nickel-chromium alloy by inductively coupled plasma mass spectrometry

The accurate determination of arsenic, selenium, tin, antimony, lead and bismuth in nickel-chromium alloy is of great significance for the production and application of nickel-chromium alloy. Due to the volatility of arsenic and selenium, a mixture of 10 mL of hydrochloric acid and 1mL of nitric acid was used to dissolve the nickel-chromium alloy. ⁷⁵As, ⁷⁷Se, ¹²⁰Sn, ¹²¹Sb, ²⁰⁸Pb and ²⁰⁹Bi were selected as the measuring isotopes. The determination method of arsenic, selenium, tin, antimony, lead and bismuth in nickel-chromium alloy by inductively coupled plasma mass spectrometry method (ICP-MS) was established using rhodium as internal standard to calibrate the determination of arsenic, selenium, tin, and antimony, and using rhenium as internal standard to calibrate the determination lead and bismuth, respectively. The experiments showed that the heating at 200 ℃ to evaporate chloride ions in the sample solution and converting the hydrochloric acid medium into nitric acid medium could eliminate the interference effect of polyatomic ions ⁴⁰Ar³⁵Cl⁺ and ⁴⁰Ar³⁷Cl⁺ ions on the determination of ⁷⁵As and ⁷⁷Se. The determination medium was further optimized: 2% (V/V) hydrochloric acid was used as the medium to determine the contents of tin, antimony, lead, and bismuth, and 2% (V/V) nitric acid-ethanol was used for the determination of arsenic and selenium contents. Under the optimized experimental conditions, the ratio of signal intensity between the analyzed element to the internal standard element showed a good linear relationship with the concentration of the analyzed element in range of 2.00-25.00 ng/mL. The correlation coefficients were greater than 0.999 5. The limits of detection were between 0.012 ng/mL and 0.21 ng/mL, and the limits of quantification were between 0.04 ng/mL and 0.70 ng/mL. The contents of arsenic, selenium, tin, antimony, lead, and bismuth in nickel-chromium alloy were determined according to the experimental method, and the found results were basically consistent with those obtained by atomic fluorescence spectrometry (AFS). The relative standard deviations (RSDs, n=11) were between 5.4% and 12%. The spiked recoveries were between 96% and 120%.