影响火花源原子发射光谱法测定不锈钢中氮元素精度的因素分析

Analysis of factors influencing the determination precision of nitrogen in stainless steel by spark source atomic emission spectrometry

从火花源原子发射光谱法(以下简称光谱法)测定不锈钢中氮元素的现状入手,以光谱法测定结果与热导法测定结果的相关性规律为主线,探讨了影响光谱法测定氮元素精度的主要因素及解决方案。结果表明,使用较新的砂轮片研磨样品、样品表面温度保持室温、采用空冷冷却样品以及旋转式清刷电极等方法均可有效提高火花源原子发射光谱法测定不锈钢中氮元素检测准确度。试验确定了仪器的最佳激发参数,并采用分段拟合的方式绘制校准曲线。当冲洗时间由8s增加至10s、预燃时间由9s增加为10s时,可大大提高火花源原子发射光谱法测定不锈钢中氮含量的检测精度。

On the basis of the current status of the determination of nitrogen in stainless steel by spark source atomic emission spectrometry （short for SS-AES）, the main factors that influenced the deter- mination precision of nitrogen by spectrometry and the solutions were discussed with correlation rules between the results of spectrometry and thermo-conductivity. It was found that the determination ac- curacy of nitrogen in stainless steel by SS-AES could be effectively enhanced by the methods, e. g. , to grind the sample with new grinding wheel, to keep the sample surface temperature at room tempera- ture, to cool the sample by air cooling or to flush the electrode at rotary mode. The optimal excitation parameters were tested and determined. The calibration curve was established by segmentation fitting method. The determination precision of nitrogen in stainless steel by SS-AES could be greatly en- hanced when the flushing time increased from 8 s to 10 s and the preburn time increased from 9 s to 10 s.