离子色谱法测定水中磷酸根的测量不确定度评定

Evaluation of measurement uncertainty for the determination of phosphate in water by ion chromatography

目的在化学分析中,过去通常把重点放在检测结果的精密度和准确度上。但是,目前很多检测活动都要求建立结果的可信度。特别是通过度量结果的可信度来证明结果的适宜性,这一般包括期望某个结果与其他结果相吻合的程度,这也是我们探究不确定度的意义。方法本文据CNAS-GL06化学分析中不确定度的评估指南,对某工业废水中磷酸根含量进行了检测,对实验过程中影响测量不确定度的分量进行了研究与分析。结果通过计算可知,当磷酸根结果为3.00 mg/L时,其可信度区间为2.86-3.14 mg/L(k=2)。结论影响其测量不确定度的主要因素是校准曲线拟合引入的不确定度。为了使检测结果更加科学准确,在日常工作中,要注意离子色谱仪的维护及保养,尽量降低仪器背景噪声,提高仪器灵敏度和准确度。

Objective In chemical analysis,the focus used to be on the precision and accuracy of detection results.However,many testing activities currently require establishing the credibility of the results.Especially by measuring the credibility of the results to prove their suitability,this generally includes the degree to which one outcome is expected to match other outcomes,which is also the significance of exploring uncertainty.Methods According to the CNASGL06 Guidelines for Evaluation of Uncertainty in Chemical Analysis,this article detected the content of phosphate ions in a certain industrial wastewater and studied and analyzed the components that affect measurement uncertainty during the experimental process.Results Through calculation,it can be concluded that when the result of phosphate ion is 3.00 mg/L,the confidence interval is 2.86-3.14 mg/L(k=2).Conclusion The main factor affecting its measurement uncertainty is the uncertainty introduced by the calibration curve fitting.In order to make the detection results more scientific and accurate,it is necessary to pay attention to the maintenance and upkeep of the ion chromatograph in daily work,minimize the background noise of the instrument,and improve the sensitivity and accuracy of the instrument.