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本文采用酚酞为内标,1-羟基2,4-苯二磺酸光度法测定水中的硝酸盐的氮含量,即在样品和标准系列中均加一定量的内标,以硝酸盐反应产物在410nm处韵吸光度与酚酞在550nm处的吸光度之比为纵座标,硝酸盐氮的含量(μg·ml~(-1))为横座标绘制标准曲线进行定量分析测定。采用内标法可根据样品浓度任意稀释体积,使吸光度(A_(410))在0.4左右,减小吸光度读数误差,简化分析手续,提高测定的准确度。试验部分一仪器与试剂 7211型分光光度计电热恒温水浴槽酚酞内标液:10ml 0.1%酚酞的60%乙醇溶液用水稀释至100ml。
In this paper, phenolphthalein as the internal standard, 1-hydroxy 2,4-benzene disulfonic acid spectrophotometric determination of nitrogen in water, that is, in both the sample and standard series plus a certain amount of internal standard nitrate reaction products in the The ratio of absorbance at 410 nm to the absorbance of phenolphthalein at 550 nm is the ordinate, and the nitrate content (μg · ml -1) is plotted against the standard curve of the abscissa for quantitative analysis. The internal standard method can be used to dilute the sample according to the sample concentration. The absorbance (A_ (410)) is about 0.4, which reduces the reading error of absorbance, simplifies the analysis procedure and improves the accuracy of the determination. Experimental part of an instrument and reagents 7211 spectrophotometer heated thermostatic water bath phenolphthalein internal standard solution: 10ml 0.1% phenolphthalein 60% ethanol solution diluted with water to 100ml.