摘要
目前测定地质样品痕量、超痕量金常用的三种方法是活性炭吸附富集-发射光谱法、泡塑吸附富集-石墨炉原子吸收光谱法、活性炭吸附富集-电感耦合等离子体质谱法，这三种方法的检出限在0．1～0．3ng／g之间，由于矿石矿物的组成非常复杂，因此在有效富集和分离的基础上，采用合适的分析手段，能够对地质样品提供满意的分析结果。为保证试样要求的灵敏度和准确性，分析方法的选择需求应根据具体试样情况和实验室条件而定。根据田口玄-博士在测量工程学中提出的信噪比（S／N）能测量系统抗干扰能力，评价测量系统的稳健性和可靠性这一观点，本文利用田口测量质量控制理论，评价地质样品中痕量、超痕量金常用的上述三种分析测试方法，对这三种分析方法三个金标准物质的测试数据进行分类处理，计算S／N值和相对标准不确定度，通过比较三者的S／N值和相对标准不确定度值，确定更为可靠的测试体系。分析结果表明，对于地质样品中痕量金（含量大于1ng／g）的测试，三种分析方法均能够满足要求；对于超痕量金（含量小于1ng／g）的测试，活性炭吸附富集一电感耦合等离子体质谱法是较好的测试方案。
There are currently three principle methods to measure trace and ultra-trace gold in geological samples, including activated carbon enrichment-Emission Spectrometry, foam enrichment-Graphite Furnace Atomic Absorption Spectrometry （GFAAS）, and activated carbon enrichment-Inductively Coupled Plasma-Mass Spectrometry （ICP-MS）. Of these, the Emission Spectrometry uses domestic equipment, with low cost and a lengthy process; the GFAAS is easy to operate but is costly as it employs an imported graphite tube. The ICP-MS method has a low detection limit but demands higher environmental conditions with high cost. The detection limits of these three methods are from 0. 1 to 0.3 ng/g. As the composition of the ore mineral is very complicated, satisfactory results for the analysis of geological samples are provided by adopting a suitable analysis method based on the effective enrichment and separation. To ensure sensitivity and accuracy of sample requirements, selection of the analysis method should follow the specific sample and laboratory conditions. According to the signal-to-noise ratio （S/N） concept proposed by Doctor Genichi Taguchi in measurement engineering, the S/N is equal to the magnitude of the mean of the process compared to its variation. The bigger the S/N, the greater the anti- interference ability, the higher sensitivity, the better the linearity, the safer, and the more reliable is the measuring system. In this paper, a description of how the Taguchi measurement quality control method was conducted to evaluate three common analysis methods for trace and ultra-trace gold measurement in geological samples for the first time is given. The measurement data obtained by the three common methods for three national standard materials were processed to calculate the S/N values and the relative standard uncertainties, respectively. By comparing the three S/N values and the relative standard uncertainties, a more stable method was selected. The experimental results show that all three analytical methods met the requirements of the trace gold measurement in geological samples, whose Au content is greater than 1 ng/g, however, the activated carbon enrichment-ICP-MS is more suited for the ultra-trace gold in samples whose Au content is less than 1 ng/g.
出处
《岩矿测试》
CAS
CSCD
北大核心
2014年第1期51-56,共6页
Rock and Mineral Analysis
关键词
田口方法
地质样品
痕量金
超痕量金
活性炭吸附富集-发射光谱法
泡塑吸附富集-石墨炉原子吸收光谱法
活性炭吸附富集-电感耦合等离子体质谱法
分析方法对比
TaguchiEmission Spectrometryenrichment -Inductivelymethod
geological samples
trace gold
ultra-trace gold
activated carbon enrichment-
foam enrichment-Graphite Furnace-Atomic Absorption Spectrometry
activated carbonCoupled Plasma-Mass Spectrometry
comparison of analytical methods
