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光度法最大灵敏度的应用
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Abstract:
以锰铁中锰测定为例,介绍了应用灵敏度概念,简化高含量光度法测定的程序:1) 根据所用光度法资料,在严格遵守“重复性测量条件”下,绘制“校准曲线”探明其吸光度上限。各个含量、吸光度的坐标点都落在同一条直线上,表明两端点连线可替代“校准曲线”,其方程为几何学的“两点式”,显示光度法的原理是ΔA = kΔC而非A = kC,灵敏度Se = ΔA/ΔC;2) 称取试样一个标准样品,制备其“母液”;3) 以“微滴”方式分取其“母液”,制备吸光度临近、但不超过的最低和最高的两个样品,实施测定;4) 以最高吸光度的含量可恰当涵盖试样最高含量为前提,选取标准样品的“母液”量,并以此为准,确定吸光度最低和最高的样品含量;5) 以吸光度最低和最高两个坐标点连线,作为样品含量的“测定线”,并根据“校准曲线”方程建立样品测定的公式;6) 根据标准样品“母液”制备方法,制备被测样品的“母液”,并以“微滴”方式分取与标准样品相同的“母液”量,制备被测样品,实施测定。以“两标准样品测定法”确定其含量。该方法简便、准确、环保。同一样品8次重复测定结果,极差为0.4%,不确定度U95为0.09% (k = 2),相对标准差RSD为0.08% (n = 8)。
Taking the determination of manganese in ferromanganese as an example, the application of the concept of sensitivity to simplify the procedure of high-content photometric determination introduced: 1) According to the photometric data used, the “calibration curve” was drawn under strict compliance with the “repeatability measurement conditions to explore its upper limit of absorbance. The coordinate points of each content and absorbance fell on the same straight line, indicating that the line connecting the two endpoints could replace the “calibration”, and its equation was the “two-point formula” in geometry, showing that the principle of photometry was ΔA = kΔC rather than A = kC, and the sensitivity Se = ΔA/ΔC; 2) Weigh a standard sample of the test sample and prepare its “mother liquor”;3) Take the “mother liquor” in the form of “microdrop” and prepare two samples with absorbance close to but not exceeding the lowest and highest , and carry out the determination; 4) Select the “mother liquor” amount of standard sample under the premise that the highest content of the sample can be properly covered, and based on this, determine the sample content with the lowest and highest absorbance; 5) Draw a straight line between the two coordinate points with the lowest and highest absorbance, which is used as the “determination line” for sample content, and establish the formula for
[1] | JJF1001-2011通用计量术语及定义[S]. 北京: 中国质量监督检验检疫总局, 2011. |
[2] | 袁秉鉴, 任屏. 对光度法的几点新认识[J]. 分析化学进展, 2019, 9(2): 132-138. |
[3] | 袁秉鉴. 高锰酸分光光度法的研究[J]. 化学分析计量, 2006, 15(2): 13-17. |
[4] | 袁秉鉴, 任屏. 沉淀物的悬浮液光度法测定[J]. 分析化学进展, 2021, 11(3): 123-131. |
[5] | 袁秉鉴. 吸光度定位光度法测定锰铁中的锰[J]. 分析化学进展, 2024, 14(3): 176-181. |
[6] | JJF1059.1-2012测量不确定度评定与表示[S]. 北京: 中国国家质量监督检验检疫总局, 2012. |
[7] | 吴诚. 机械工程材料测试手册(化学卷) [M]. 沈阳: 辽宁科学技术出版社, 1996: 1046. |
[8] | 高立红, 周凯红, 王燕霞, 等. 硅钼蓝分光光度法测定氟化稀土中二氧化硅[J]. 冶金分析, 2017, 37(4): 57-61. |
[9] | 邓军华, 王一凌, 亢德华, 等. 二安替吡啉甲烷光度法测定含钛物料中二氧化钛[J]. 冶金分析, 2015, 35(10): 30-35. |
[10] | 钟国秀, 黄清华. 光度法快速测定铜合金中微量铝[J]. 化学分析计量, 2011, 20(5): 60-62. |
[11] | 王冀艳, 刘勉, 赵晓亮, 等. 酸溶-苯基荧光酮光度法测定矿样中钽[J]. 冶金分析, 2017, 37(4): 48-51. |
[12] | 王璇, 金涛, 王浩伟, 等. 紫外分光光度法测定聚硫密封胶中二氧化钛[J]. 化学分析计量, 2017, 26(4): 24-27. |
[13] | 袁秉鉴. “精密度法则”在分光光度法中的作用[J]. 分析化学进展, 2020, 10(1): 1-7. |
[14] | 王玉枝, 张正奇, 宦双燕, 等. 分析化学[M]. 第3版. 北京: 科学出版社, 2016: 198. |
[15] | 杨振明. 概率论[M]. 第2版. 北京: 科学出版社, 2008: 74. |
[16] | GB/T4883-2008数据的统计处理和解释正态样本离群值的判断和处理[S]. 北京: 中国国家质量监督检验检疫总局, 2008. |
[17] | 袁秉鉴. 紫铜滴定分析与“尾数微滴”法[J]. 理化检验(化学分册), 1987, 23(1): 11-14. |
[18] | 袁秉鉴. 等滴光度法测定钼铁中的钼[J]. 化学分析计量, 2002, 11(5): 15-17. |