Abstract：The determination of trace elements in Geological Samples by Atomic Absorption Spectrometry is simple, rapid, accurate and economical, which has been widely used in geological laboratories. However, the complex pre-processing process and testing process will inevitably introduce uncertainty. According to the general requirements for the competence of inspection and calibration laboratories, the uncertainty of measurement results should be properly evaluated. In this study, the concentration of Cu, Pb, and Zn in the national standard rock sample and a core sample from the Qujia gold mine in Jiaodong were determined by Atomic Absorption Spectrometry after electric heating plate digestion. Three times the standard deviation of the blank samples test results was calculated as the detection limits. The results of the standard samples and core samples are by the requirements of DZ/T 0130.3—2006 on the accuracy and precision of the test. The bottom-up method was used to evaluate the uncertainty of results in the laboratory. The sources of measurement uncertainty were determined, including sample weighing, constant sample volume, sample digestion, preparation of standard series, least-square fitting and repeated measurement. The value and expanded uncertainty of six uncertainty components were accurately calculated. Among them, the last four components are the main sources of uncertainty. The results show that the uncertainty of the measurement results ofcopper, lead, and zinc in the standard samplesaresmaller than the uncertainty given in the standard certificate, the concentration of Cu, Pb, and Zn in the core sample is (4.965±0.383), (36.415±2.449), (30.818 0±0.736) μg·g-1, respectively. The uncertainty of six sources is compared, and some improvements are put forward when the content of Cu, Pb, and Zn in rock samples is measured by this method: adjusting the sampling mass or constant volume to improve the concentration and absorbance of elements in the solution to be measured, adjusting the concentration of standard series to make it close to the concentration of elements in the solution to be measured, increase the measurement times of standard point and the solution to be measured, the pipette with small relative standard uncertainty should be used as much as possible if necessary in order to reduce the measurement uncertainty. Evaluating measurement uncertainty as an effective tool to guide the improvement of analytical methods and test process is of great significance in the accurate determination of trace elements in rock samples.
[1] WANG Zeng-huan, WANG Xu-nuo（王增焕，王许诺）. Metallurgical Analysis（冶金分析）, 2014, 34(2): 44.
[2] SONG Zu-feng, LU Xiang-dong, WANG Zhong-le, et al（宋祖峰，陆向东，王忠乐，等）. Metallurgical Analysis（冶金分析）, 2020, 40(9): 31.
[3] KUAI Li-jun, ZHAN Xiu-chun, FAN Xing-tao, et al（蒯丽君，詹秀春，樊兴涛，等）. Rock and Mineral Analysis（岩矿测试）, 2013, 32(6): 903.
[4] HU Jian-ping, WANG Ri-zhong, DU Bao-hua, et al（胡健平，王日中，杜宝华，等）. Rock and Mineral Analysis（岩矿测试）, 2018, 37(4): 388.
[5] HE Pan-hong, YANG Zhen, GONG Zhi-xiang（贺攀红，杨 珍，龚治湘）. Rock and Mineral Analysis（岩矿测试）, 2020, 39(2): 235.
[6] State Administration for Market Regulation（国家市场监督管理总局）. GB/T 27025—2019/ISO/IEC 17025: 2017, IDT. General Requirements for the Competence of Testing and Calibration Laboratories(校验和校准实验室能力的通用要求). Beijing: Standards Press of China（北京：中国标准出版社）, 2019.
[7] Milde David, Pluhacek Tomas, Kuba Martin, et al. Talanta, 2020, 220: 121386.
[8] Uemoto Michihisa, Makino Masanori, Ota Yuji, et al. Analytical Sciences, 2018, 34(6): 719.
[9] Padmasubashini V, Hanuman V, Singh S B, et al. Atomic Spectroscopy, 2019, 40(5): 179.
[10] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. GB/T 14506.18—2010. Methods for Chemical Analysis of Silicate Rocks-Part 18: Determination of Copper Content(硅酸盐岩石化学分析方法 第18部分：铜量测定). Beijing: Standards Press of China（北京：中国标准出版社）, 2011.
[11] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. GB/T 14506.19—2010. Methods for Chemical Analysis of Silicate Rocks-Part 19: Determination of Lead Content(硅酸盐岩石化学分析方法 第19部分：铅量测定). Beijing: Standards Press of China（北京：中国标准出版社）, 2011.
[12] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. GB/T 14506.20—2010. Methods for Chemical Analysis of Silicate Rocks-Part 20: Determination of Zinc Content(硅酸盐岩石化学分析方法 第20部分：锌量测定). Beijing: Standards Press of China（北京：中国标准出版社）, 2011.
[13] Bich W, Cox M G, Harris P M. Metrologia, 2006, 43: S161.
[14] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. GB/T 27418—2017. Guide to the Evaluation and Expression of Uncertainty in Measurement(测量不确定度评定和表示). Beijing: Standards Press of China（北京：中国标准出版社）, 2018.
[15] Ministry of Environmental Protection（环境保护部）. HJ 168-2020. Environmental Monitoring-Technical Guideline on Drawing and Revising Analytical Method Standards(环境监测分析方法标准制订技术导则). Beijing: China Environmental Press（北京：中国环境科学出版社）, 2021.
[16] Ministry of Land and Resources of the People’s Republic of China（中华人民共和国国土资源部）. DZ/T 0130.3—2006. The Specification of Testing Quality Management for Geological Laboratorites-Part 3: Chemical Components Analysis of Rock and Mineral Samples(地质矿产实验室测试质量管理规范；第三部分 岩石矿物样品化学成分分析). Beijing: Standards Press of China（北京：中国标准出版社）, 2006.
[17] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. JJF 1036—2008. Verification Regulation of Electronic Balance(电子天平检定规程). Beijing: China Quality Supervision Press（中国质检出版社）, 2008.
[18] General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China（中华人民共和国国家质量监督检验检疫总局）. JJG 196-2006. Verification Regulation of Working Glass Container(常用玻璃器皿检定规程). Beijing: China Metrology Publishing House（北京：中国计量出版社）, 2007.
