摘要
均匀性检验是环境标准样品研制的重要技术环节,在均匀性检验过程中,数据漂移对环境标准样品均匀性判定及其不确定度评定的影响不容忽视。本文结合实例,从实验方案和数理统计方法等方面探讨了随机分析法、随机区组法、内插校正法、趋势分析校正法等均匀性检验实验方案及数据漂移校正方法。提出采用t检验法判断数据漂移的显著性,在数据漂移趋势不显著的情况下,采用随机分析法进行标准样品的均匀性检验。在数据漂移显著的情况下,宜采用内插校正法或趋势分析校正法对均匀性数据进行漂移校正。以某土壤中Ni元素均匀性检验为例,经采用内插校正法和趋势分析校正法校正漂移数据后,测量值的相对标准偏差(RSD)由3.0%分别下降为1.4%和1.2%,直线模型斜率的绝对值由0.2003 mg/kg分别下降为0.02870mg/kg和4.709×10-5mg/kg。土壤中Ni、Cu、Co、Tl等4种重金属元素的瓶间均匀性不确定度分量(ubb)与随机分析法相比,下降最高达78%。在长时间分析测试过程中数据漂移校正效果欠佳的情况下,宜采用随机区组法进行标准样品的均匀性检验。
BACKGROUND:Assessment of homogeneity of Environmental Reference Material(ERM)is one of the most important steps for the development of an ERM.The data drift has a serious negative effect on the assessment of homogeneity and uncertainty of ERM.OBJECTIVES:To develop the drift correction methods for homogeneity test of ERM.METHODS:The drift correction methods were discussed from the aspects of experimental scheme and statistical methods through practical cases.The drift correction methods,such as random analysis,randomized block design,interpolation correction,and trend analysis correction,were introduced in details.RESULTS:The t-test method was proposed to judge the significance of data drift.For insignificant drift trend,the random analysis method was useful for the evaluation of uncertainty of homogeneity.If the drift trend was significant,better-corrected results were obtained by using interpolation correction and trend analysis correction methods.For example,after data correction by interpolation correction and trend analysis,the relative standard deviation(RSD)of homogeneity data of Ni in soil decreased from 3.0%to 1.1%and 0.84%,respectively.The absolute value of slope of line decreased from 0.2003mg/kg to 0.02870mg/kg and 4.709×10-5 mg/kg.The uncertainties of between-bottle homogeneity of Ni,Cu,Co and Tl decreased by 78%compared with the random analysis method.CONCLUSIONS:Data drift correction methods are not effective for long periods of measurement,therefore the experimental scheme of randomized block design method is recommended for homogeneity study.
作者
田衎
贺岩涛
张覃
郭伟臣
赵亚娴
岳亚萍
杨永
TIAN Kan;HE Yan-tao;ZHANG Qin;GUO Wei-chen;ZHAO Ya-xian;YUE Ya-ping;YANG Yong(Institute of Environmental Reference Materials,Ministry of Ecology and Environment,State Environmental Protection Key Laboratory of Pollutant Metrology and Reference Materials,Beijing 100029,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2020年第3期425-433,共9页
Rock and Mineral Analysis
基金
国家环境标准制修订项目(2018-24)。
关键词
环境标准样品
均匀性评价
漂移校正
内插校正法
趋势分析校正法
随机区组法
environmental reference materials
homogeneity assessment
data drift correction
interpolation correction method
trend analysis correction method
randomized block design method
