石墨炉原子吸收法直接测定铁镍基高温合金中痕量锑

Direct Determination of Trace Antimony in Iron-nickel-base Superalloy by Graphite Furnace Atomic Absorption Spectrometry Method

试验采用石墨炉原子吸收光谱法测定铁镍基高温合金中的锑,选取Sb 217.58 nm谱线作为分析线,分光宽带0.7 nm。试验通过研究基体效应、溶样酸、基体改进剂、灰化和原子化温度条件以及不同激发光源类型,以选出测定铁镍基高温合金中锑的最优试验方案。结果表明:选用2 mL盐酸和0.4 mL硝酸溶解样品,加入基体改进剂为0.003 mg Pd(NO_3)_2+0.03 mg NH_4H_2PO_4,灰化温度为1200℃,原子化温度为2000℃,采用铁镍基标准样品建立工作曲线,以作为测定铁镍基高温合金中锑的最佳方案。同时通过对比两不同激发光源下的校准曲线和测定结果的准确度和精密度,表明在两不同光源条件下其测定结果均能满足试验要求。尤其在EDL光源条件下,试验获得了更好的校准结果(R^2=0.9992)、短期稳定性(RSD<8.0%,n=8)和方法检出限。在这两类光源条件下锑的检出限分别为0.86μg/L(HCL)和0.23μg/L(EDL)。

Antimony in iron-nickel-base superalloy was determined by graphite furnace atomic absorption spectrometry method （GFAAS）. Sb 217.58 nm spectral lines was selected the analytical lines, spectral bandwidth was 0.7 nm. In order to select the optimum experimental scheme for determination of antimony in iron-nickel-base superalloy, matrix effect, dissolved sample acid, matrix modifier, pyrolysis temperature and atomization temperature conditions as well as different excitation light source types were investigated. The experimental results showed that select 2 milliliter hydrochloric acid and 0.4 milliliter nitric acid to dissolve sample, add 0.003 milligram Pd（NO3）2 and 0.03 milligram NH4H2PO4 as matrix modifier, pyrolysis temperature is 1200 ℃ and atomization temperature is 2000 ℃, use iron-nickel-base standard samples to built working curve, are the optimum experimental scheme for determination of antimony in iron-nickel-base superalloy. Meanwhile, by comparing with calibration curves and accuracy and precision of determination results with different excitation light sources, which showed determination results satisfy with experimental requirement. Especially under the condition of EDL light source, experiment obtained a better calibration result （R-＇=0.9992）, short-term stability （RSD〈8.0%, n=8） and method detection limit. Detection limit of antimony element was 0.86 μg/L （HCL） and 0.23 μg/L （EDL） under the conditions of two types excitation light source, respectively.