火花放电原子发射光谱仪分析不锈钢的长期稳定性

实验室环境等因素的变化会带来仪器分析误差,测量结果超出允许限度。因此,测量仪器的长期稳定性时间上限十分必要。实验选用火花放电原子发射光谱中3种不同成分梯度的不锈钢有证标准物质,对火花放电原子发射光谱中的C、Si、Mn、S、P、Cr、Ni、Mo、Cu、Ti、V、Co每个时段测量结果的精密度和正确度、时段内重复性、时段间总精密度、总平均值的正确度进行考察。结果表明,C、Si、Mn、S、P、Cr、Ni、Cu、Ti分别在连续7.5、7.0、12.0、8.0、4.0、7.5、7.0、14.5和10.0 h的测量时间内,Mo、V、Co在15.0 h测量时间内,各时段内精密度、正确度,时段内重复性,时段内总精密度,总平均值正确度均满足检测标准和统计要求,因此,仪器长期稳定性时间上限T_MAX为4.0 h。通过长期稳定性的测定,减少了标准样品或控制样品的使用频率,节省了时间和成本,对炉前快速分析很有价值。

Long-term stability of spark discharge atomic emission spectrometer in analysis of stainless steel

The changes of factors such as environment in laboratory will lead to instrumental analysis error, which makes the measured results exceed the allowed limits. Therefore, it is necessary to measure the upper time limit of long-term stability of the measuring instrument. In experiments, three certified reference materials of stainless steel with different composition gradients were determined by spark discharge atomic emission spectrometry. The precision and trueness of determination results of C, Si, Mn, S, P, Cr, Ni, Mo,Cu, Ti, V and Co in each period, the precision within the period, the total precision between periods and the trueness of the total average value were analyzed. The results showed that the precision and trueness, repeatability within the period, general precision within the period and trueness of the total average value could meet the checking standard and statistical requirements within the following consecutive periods: 7.5, 7.0, 12.0, 8.0, 4.0, 7.5, 7.0, 14.5 and 10.0 h for C, Si, Mn, S, P, Cr, Ni, Cu and Ti, respectively, and 15.0 h for Mo, V and Co. Therefore, the upper time limit of long-term stability of the measuring instrument T_MAX was 4.0 h. Through the long-term stability test, the use frequency of certified reference materials(CRMs) or control sample was reduced, which not only saved time and cost, but also was valuable for the quick analysis of on-the-spot samples.