Determination of Dissolved Oxygen in Water by Micro-Weighing-Titration with a Polythene Capillary Burette
摘 要
将微量称量滴定法应用于硫代硫酸钠-碘量法测定水中溶解氧的含量.在滴定中采用自制的聚乙烯毛细滴定管代替了国标GB 10738-1989中所规定使用的结构复杂精细的称量滴定装置.操作时,在聚乙烯毛细滴定管中吸满了Na2S2O3标准溶液,在精密电子天平上称得滴定前后(以淀粉为指示剂)毛细滴定管及滴定剂的总质量.从滴定中所耗Na2S2O3标准溶液的质量按文中所给出的公式即可计算水样中的溶解氧含量,所制作的毛细管滴定管每滴滴定剂的质量要求控制在0.005~0.010 g之间,滴定过程的相对偏差可控制在1.0%左右.由于滴定系在微量水平上进行,因此方法具有消耗试剂少,操作快速而方便,且能取得优于国标方法的准确度和精密度,对4个水样进行分析,测得结果的相对标准偏差值(n=7)在0.18%~0.66%之间,明显小于国标方法测定结果的相对标准偏差(0.43%~1.26%).
Abstract
In the iodometric titration of dissolved oxygen in water,weighing titration with Na2S2O3 standard solution was applied.A self-made polythene capillary burette was used in the titration instead of the complex and precise weighing titration deviced specified in the standard GB 10738-1989.The polythene capillary burette was filled with standard solution of Na2S2O3,and the total mass of the burette and titrant was weighed on a precise electronic balance before and after the titration using starch as indicator.Amount of dissolved oxygen in the sample was calculated from the mass of Na2S2O3 standard solution according to the formula given in the paper.One drop of titrant from the capillary burette was qualified to have the mass in the range from 0.005-0.010 g.Relative deviation of the titration process was controlled around 1.0%.Titration of the proposed method was made on a micro scale,thus resulting less comsuption of reagents,more rapid and convenient in operation,as well as better accuracy and precision than the GB standard method.Values of RSD′s (n=7) obtained in analysis of 4 water samples were ranging from 0.18%-0.66% which were smaller than those obtained by the GB method (0.43%-1.26%).
中图分类号 X832 O655.21
所属栏目 工作简报
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收稿日期 2007/6/11
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备注蔡成翔(1964-),男,壮族,广西百色市人,副教授,主要从事水质分析研究.
引用该论文: CAI Cheng-xiang. Determination of Dissolved Oxygen in Water by Micro-Weighing-Titration with a Polythene Capillary Burette[J]. Physical Testing and Chemical Analysis part B:Chemical Analysis, 2007, 43(10): 844~846
蔡成翔. 毛细滴管称量滴定法测定水中溶解氧[J]. 理化检验-化学分册, 2007, 43(10): 844~846
被引情况:
【1】方原民, "高精度蠕动泵式称量滴定装置及称量滴定方法",理化检验-化学分册 50, 245-246(2014)
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参考文献
【1】GB 7489-1987水质 溶解氧的测定 碘量法[S].
【2】GB/T 15455-1995工业循环冷却水中溶解氧的测定 碘量法[S].
【3】GB 10738-1989工作基准试剂(容量)称量滴定法通则[S].
【4】王桂花.EDTA二级溶液标准物质的研制[J].化工标准·计量·质量,2001,5:41-43.
【5】蔡成翔.毛细滴管-吸量管数滴微型滴定法现场快速测定水的总硬度[J].工业水处理,2006,26(12):70-73.
【6】蔡成翔,沈文闻.毛细滴管数滴微型滴定法野外快速测定水中溶解氧[J].分析科学学报,2007,23(2):231-234.
【7】GB/T 601-2002化学试剂标准溶液的制备[S].
【8】JJG 196-1990常用玻璃量器检定规程[S].
【2】GB/T 15455-1995工业循环冷却水中溶解氧的测定 碘量法[S].
【3】GB 10738-1989工作基准试剂(容量)称量滴定法通则[S].
【4】王桂花.EDTA二级溶液标准物质的研制[J].化工标准·计量·质量,2001,5:41-43.
【5】蔡成翔.毛细滴管-吸量管数滴微型滴定法现场快速测定水的总硬度[J].工业水处理,2006,26(12):70-73.
【6】蔡成翔,沈文闻.毛细滴管数滴微型滴定法野外快速测定水中溶解氧[J].分析科学学报,2007,23(2):231-234.
【7】GB/T 601-2002化学试剂标准溶液的制备[S].
【8】JJG 196-1990常用玻璃量器检定规程[S].
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