Determination of Trace Lead in Uranium-bearing Geological Samples by Inductively Coupled Plasma-Optical Emission Spectrometry with Double Capillary On-line Interference Correction
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摘要:
应用电感耦合等离子体发射光谱法测定地质样品中的铅时, 基体元素的干扰会使测量结果偏低。本文用氢氟酸、硝酸、高氯酸、盐酸溶解样品, 采用等径双毛细管在线干扰校正的方法测定了含铀地质样品中的微量铅。首先通过双毛细管确定了样品溶液中的Fe、Al对铅有负干扰, 而一定浓度的U、Ba、Ti、Ca、Mn、K、Mg、Na等基体元素没有干扰或可以忽略, 由此在线双毛细管根据样品中Fe、Al的含量使用不同的校正试液建立标准曲线, 测定未知样品时同步进行稀释, 降低了Fe、Al的基体效应。方法检出限为1.5 μg/g, 精密度(RSD)小于5%。与普通干扰校正法相比, 双毛细管在线干扰校正法可根据不同基体的样品使用不同的干扰校正试液, 快速建立标准曲线进行复杂样品的测定, 且避免了二次稀释, 节省试剂, 适合测定基体成分接近的批量样品。
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关键词:
- 含铀地质样品 /
- 微量铅 /
- 双毛细管 /
- 在线干扰校正 /
- 电感耦合等离子体发射光谱法
Abstract:Measured lead contents in geological samples were commonly lower than real values because of matrix elements interference during Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) analyses. In this study, U-bearing geological samples were dissolved by hydrofluoric acid, nitric acid, perchloric acid, and hydrochloric acid. Trace lead was determined by ICP-OES with double capillary on-line interference correction. The interferences of matrix elements on lead were studied using double capillary. Iron and Al had negative interferences on lead, whereas a specific concentration of U, Ba, Ti, Ca, Mn, Mg, K and Na almost had no interferences on lead. The standard curve was established using double capillary according to the contents of Fe and Al in different test solution. The unknown sample was diluted simultaneously, which reduced the matrix effects of Fe and Al. The detection limit was 1.5 μg/g, and the RSD was less than 5%. Compared with the common interference correction method, the double capillary on-line interference correction method can establish a standard curve quickly using different interference correction test solutions according to different matrices. Moreover, sample solution does not need to be secondly diluted, saving the reagent. This method is suitable for rapid determination of batch samples with similar matrices.
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表 1 实验样品中的元素含量
Table 1. Composition of elements in sample
元素 含量范围
(%)元素 含量范围
(%)U 0.001~0.05 Al 5.0~6.5 Pb 0.005~0.5 Mn 1.0~3.0 Fe 3.0~6.5 Ba 0.05~0.5 Ti 0.27~0.76 K 1.5~2.5 Na 1.0~1.3 Ca 3.2~4.0 Mg 1.0~2.4 表 2 不同干扰校正方法测定铅的结果比较
Table 2. Analytical results of Pb determined by different interference correction methods
能力比对
样品编号铅含量(μg/g) 参考值 直接测定法
测定值普通干扰校正法
测定值双毛细管在线干扰
校正法(本法)测定值样品1# 137 114 133 148 样品2# 416 406 409 412 注:表格中列出的“参考值”为中核集团地矿事业部委托核工业北京地质研究院组织的铀矿地质样品分析实验室间比对结果中位值,此中位值是由24家实验室比对结果统计计算得出。其中1#、2#为2012年比对样品。 表 3 国家标准物质和比对样品分析结果
Table 3. Analytical results of Pb in national reference material and constrast samples
标准物质和能力
比对样品编号铅含量(μg/g) 相对误差
(%)RSD
(%)本法 参考值 GBW04118 67.1 63.5 5.67 1.2 样品3# 3319.8 3370* -1.49 2.0 样品4# 2084.7 2066* 0.91 1.1 样品5# 1326.9 1272* 4.32 1.1 样品6# 1167.7 1148* 1.72 1.6 注:表格中列出的“参考值”为中核集团地矿事业部委托核工业北京地质研究院组织的铀矿地质样品分析实验室间比对结果中位值,此中位值是由24家实验室比对结果统计计算得出。其中3#、4# 、5#、6#为2014年比对样品。 表 4 实际样品分析结果
Table 4. Analytical results of Pb in practical samples
客户送检
样品编号铅含量(μg/g) 回收率
(%)测定值 加标量 测得总量 样品1 986.3 1000 1975.4 98.9 样品2 560.7 500 1067.7 101.4 样品3 236.2 250 496.6 104.2 -
[1] [2] [3] [4] doi: 10.11792/hj201501019
[5] [6] [7] [8] [9] [10] [11] [12] [13] [14] -