ISO 7393-2:2017 水的质量 游离氯和氯的总含量测定 第2部分：为常规检验目的使用的N,N-二乙基-1,4-苯二胺比色法

标准编号：ISO 7393-2:2017

中文名称：水的质量 游离氯和氯的总含量测定 第2部分：为常规检验目的使用的N,N-二乙基-1,4-苯二胺比色法

英文名称：Water quality — Determination of free chlorine and total chlorine — Part 2: Colorimetric method using N,N-dialkyl-1,4-phenylenediamine, for routine control purposes

发布日期：2017-12

标准范围

ISO 7393-2:2017规定了一种测定水中游离氯和总氯的方法，适用于实验室和现场测试。它基于光度计中的吸收、红色DPD颜色复合物或颜色强度的测量，通过将颜色与定期校准的标准比例尺进行目视比较。该方法适用于饮用水和其他水，其中溴、碘和其他氧化剂等其他卤素的含量几乎可以忽略不计。海水和含有溴化物和碘化物的水是一组需要执行特殊程序的水。该方法在实践中适用于氯（Cl2）浓度，例如从0000 4 mmol/l到0,07 mmol/l（e。g、 0.03 mg/l至5 mg/l）总氯。对于较高浓度，稀释试验部分。通常，该方法作为现场方法使用，带有移动光度计和商用现成试剂（液体试剂、粉末和片剂）。这些试剂必须符合最低要求，并包含基本试剂和缓冲系统，该缓冲系统适用于将测量溶液的pH值调整到通常为6.2至6.5的范围。如果怀疑水样的pH值和/或缓冲容量不常见，用户必须进行检查，并在必要时将样品pH值调整至所需范围。样品的pH值在pH值4和8的范围内。如有必要，在试验前用氢氧化钠溶液或硫酸进行调整。附录A中给出了区分一氯胺型组合氯、二氯胺型组合氯和三氯化氮形式组合氯的程序。附录C中给出了饮用水和其他低污染水中游离氯和总氯的测定程序，用于使用介观流体通道泵/色度计的一次性平面试剂填充反应杯。

ISO 7393-2:2017 specifies a method for the determination of free chlorine and total chlorine in water, readily applicable to lab- and field-testing. It is based on measurement of the absorption, the red DPD colour complex in a photometer or the colour intensity by visual comparison of the colour with a scale of standards that is regularly calibrated.This method is appropriate for drinking water and other waters, where additional halogens like bromine, iodine and other oxidizing agents are present in almost negligible amounts. Seawater and waters containing bromides and iodides comprise a group for which special procedures are to be carried out.This method is in practice applicable to concentrations, in terms of chlorine (Cl2), from, for example, 0,000 4 mmol/l to 0,07 mmol/l (e.g. 0,03 mg/l to 5 mg/l) total chlorine. For higher concentrations, the test portion is diluted.Commonly, the method is applied as a field method with mobile photometers and commercially available ready-for-use reagents (liquid reagents, powders and tablets). It is essential that those reagents comply with minimum requirements and contain the essential reagents and a buffer system suitable to adjust the measurement solution to a pH range of typically 6,2 to 6,5. If there is doubt that water samples have uncommon pH values and/or buffer capacities, the user has to check and, if necessary, to adjust the sample pH to the required range. The pH of the sample is within the range of pH 4 and 8. Adjust, if necessary, with sodium hydroxide solution or sulfuric acid before the test.A procedure for the differentiation of combined chlorine of the monochloramine type, combined chlorine of the dichloramine type and combined chlorine in the form of nitrogen trichloride is presented in Annex A. In Annex C, a procedure is presented for the determination of free and total chlorine in drinking and other low polluted waters, for disposable planar reagent-filled cuvettes using a mesofluidic channel pump/colorimeter.

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