COD_(Mn)计算公式的正确选用对实验室质控的影响
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摘要
高锰酸盐指数测定水中还原性物质浓度,是水资源质量评价体系中的主要指标。GB11892-89有分别适用于非稀释和稀释样品的公式。实际操作中,分析人员常将多种样品一批次分析,统一使用非稀释公式处理数据,对使用标准物质作实验室质量控制非常不利。采用理论结合实验探讨数据处理的方法。结果表明:标准物质高锰酸盐指数浓度值用非稀释公式计算的结果大于用稀释公式计算的结果,导致标准物质对未稀释的水样的实验室质量控制失效。对标准物质和非稀释水样应分别使用稀释公式和非稀释公式计算。公式的正确选用对提高实验数据可靠性、优化河流、湖库富营养化评价工作具有重要意义。
The determination of the concentration of reducing substances in water by permanganate index is the main indicator in the water quality assessment system. GB11892-89 has formulas for undiluted and diluted samples, respectively. In practice, analysts often analyze multiple samples in batches and use the non-dilution formula to process data. It is very unfavorable to use standard materials for laboratory quality control. The method of data processing is explored by combining theory with experiments. The results show that the results of the standard substance permanganate index concentration value calculated by the non-dilution formula are larger than those calculated by the dilution formula, which results in the failure of the standard substance to control the laboratory quality control of the undiluted water sample. Standard and non-dilution water samples should be calculated using the dilution formula and the non-dilution formula, respectively. The correct selection of formulas is of great significance for improving the reliability of experimental data and optimizing the evaluation of eutrophication of rivers and lakes.
The determination of the concentration of reducing substances in water by permanganate index is the main indicator in the water quality assessment system. GB11892-89 has formulas for undiluted and diluted samples, respectively. In practice, analysts often analyze multiple samples in batches and use the non-dilution formula to process data. It is very unfavorable to use standard materials for laboratory quality control. The method of data processing is explored by combining theory with experiments. The results show that the results of the standard substance permanganate index concentration value calculated by the non-dilution formula are larger than those calculated by the dilution formula, which results in the failure of the standard substance to control the laboratory quality control of the undiluted water sample. Standard and non-dilution water samples should be calculated using the dilution formula and the non-dilution formula, respectively. The correct selection of formulas is of great significance for improving the reliability of experimental data and optimizing the evaluation of eutrophication of rivers and lakes.
引文