WO2024007482A1 - 一种用于氨氮检测的固体试剂及其检测方法 - Google Patents

一种用于氨氮检测的固体试剂及其检测方法 Download PDF

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WO2024007482A1
WO2024007482A1 PCT/CN2022/126386 CN2022126386W WO2024007482A1 WO 2024007482 A1 WO2024007482 A1 WO 2024007482A1 CN 2022126386 W CN2022126386 W CN 2022126386W WO 2024007482 A1 WO2024007482 A1 WO 2024007482A1
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ammonia nitrogen
detection
sodium
parts
reagent
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French (fr)
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何苗
刘丽
朱启运
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清华大学
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N2021/775—Indicator and selective membrane

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  • the invention belongs to the technical field of water quality detection, and specifically relates to a solid reagent for ammonia nitrogen detection and a detection method thereof.
  • Ammonia nitrogen in water is an important indicator of water quality testing and one of the important indicators for judging whether a water body is eutrophic. It not only affects the ecology, but also harms the survival of organisms.
  • Ammonia nitrogen refers to the collective name for free ammonia and ionic ammonium in water. Compared with ammonium ion NH 4 + , ammonia NH 3 is easier for organisms to pass through biofilms. Therefore, the toxicity of ammonia nitrogen mainly refers to the toxicity of NH 3 [1] , and its toxicity is positively related to the alkalinity of the solution. , when the solution pH or temperature increases. The proportion of NH 3 is higher, and conversely the proportion of NH 4 + is higher [2] .
  • the object of the present invention is to provide a solid reagent for ammonia nitrogen detection.
  • the solid reagent for ammonia nitrogen detection provided by the present invention includes the following components by mass: 2.4-3.6 parts of sodium salicylate, 0.08-0.12 parts of sodium hydroxide, 0.08-0.12 parts of potassium sodium tartrate, dichloroisosodium Sodium cyanurate dihydrate 0.04-0.06 parts, sodium nitroprusside 0.04-0.06 parts.
  • the solid reagent for ammonia nitrogen detection includes the following components by mass: 3.0 parts of sodium salicylate, 0.1 part of sodium hydroxide, 0.1 part of potassium sodium tartrate, and sodium dichloroisocyanurate dihydrate 0.05 parts of sodium nitroprusside.
  • the solid reagent for ammonia nitrogen detection can also be composed of the following components by mass: 3.0 parts of sodium salicylate, 0.1 part of sodium hydroxide, 0.1 part of potassium sodium tartrate, sodium dichloroisocyanurate Hydrate 0.05 parts, sodium nitroprusside 0.05 parts.
  • the solid reagent for ammonia nitrogen detection can be provided in the form of a reagent package or commercialized.
  • the reagent package for ammonia nitrogen detection can specifically consist of the following components: 3.0g sodium salicylate, 0.1g sodium hydroxide, 0.1g sodium potassium tartrate, 0.05g sodium dichloroisocyanurate dihydrate, nitroprusside Sodium 0.05g.
  • the reaction mechanism of the solid reagent for ammonia nitrogen detection is the salicylic acid colorimetric reaction mechanism, specifically as follows: under alkaline conditions and the catalytic action of potassium nitrosoferricyanide, ammonia and ammonium radicals in the water The ions react with salicylate by hypochlorite ions to produce indophenol blue, a blue substance. The absorbance is measured with a spectrophotometer at a wavelength of 697nm to calculate the concentration of ammonia nitrogen in the water.
  • the main developer of salicylic acid method is salicylic acid and salicylate compounds. Since salicylic acid has low activity at normal temperature and pressure and is slightly soluble in water, if water is used, Cylic acid as a color developer usually increases the amount used [7] . Therefore, a simpler salicylate with higher solubility, namely sodium salicylate, is selected as the color developer in the present invention.
  • the oxidizing agent is selected as hypochlorite based on the reaction mechanism.
  • the common hypochlorite is sodium hypochlorite, but since sodium hypochlorite solution has poor stability and is easy to decompose, sodium dichloroisocyonurate is selected as a stable oxidant.
  • Cyanide salts play a key role as catalysts in the measurement of ammonia nitrogen by the salicylic acid method.
  • sodium nitroprusside is one of the catalysts with better catalytic effect and stability among cyanide salts and is the most widely used. Therefore, it is the best choice to select sodium nitroprusside as the catalyst in the present invention.
  • the overall chromophore is alkaline, but metal elements such as Fe, Mg and other metal ions in the water will form hydroxide precipitates under alkaline conditions, so the masking agent is indispensable.
  • Tartrate and citrate are both common and very effective masking agents. However, when using citrate as a masking agent, the amount of coexisting ions is larger, and of course the test requirements will be higher [8] . In comparison, Tartrate as a masking agent is more suitable for the system of this study, and potassium sodium tartrate was selected as the masking agent of this study.
  • Control of the pH value of the system of the present invention In the sodium nitroprusside-catalyzed salicylate system, the absorbance with a pH value in the range of 11.54 to 1.97 is the best and most stable, so in this system, the amount of sodium hydroxide is used to control the pH value. Control the pH of the system.
  • the solid reagent for ammonia nitrogen detection described in the present invention can be specifically used for water quality ammonia nitrogen detection.
  • the solid reagent for ammonia nitrogen detection is suitable for emergency rapid detection and analysis of groundwater, pipe network water, and wastewater.
  • the present invention also provides a method for detecting ammonia nitrogen in water quality using the above-mentioned solid reagent for ammonia nitrogen detection.
  • the method provided by the invention includes the following steps:
  • each reagent package is suitable for ammonia nitrogen detection of 10 mL water sample.
  • the reaction time (color development time) is not less than 10 minutes. In an indoor and outdoor environment of no less than 5°C, the reaction time can be specifically 10 minutes.
  • step (1) of the above method if the pH value of the water sample to be tested is greater than 9.0 or less than 5.0, the pH value needs to be adjusted to 7.0 before detection.
  • step (2) of the above method the ultraviolet spectrophotometer measures the absorbance at a wavelength of 697 nm.
  • the above method can be used to detect water samples with ammonia nitrogen concentration ranging from 0.03 to 2.50 mg/L. If the ammonia nitrogen concentration in the water sample to be tested exceeds this range, it can be appropriately diluted before testing.
  • the present invention has the following beneficial effects:
  • the ammonia nitrogen detection solid reagent provided by the invention can meet the high requirements of portability and accuracy in water quality detection work, and has good application prospects. In addition, compared with imported ammonia nitrogen detection reagents, they are more expensive, have longer ordering cycles, longer transportation times, poor stability, and are more sensitive to temperature and usage.
  • the ammonia nitrogen detection solid reagent of the present invention is also similar in this respect. Has good development prospects. This formula is simple, fast, and accurate, and is suitable for emergency rapid detection and analysis of groundwater, pipe network water, and wastewater.
  • Figure 1 is the standard curve for measuring ammonia nitrogen using the HJ 536-2009 method
  • Figure 2 shows the solid reagent before grinding (left picture) and the reagent powder after grinding (right picture);
  • Figure 3 is an ammonia nitrogen detection reagent package provided by the present invention.
  • Figure 4 is a diagram showing the dosage evaluation of sodium nitroprusside in the present invention.
  • Figure 5 is an evaluation diagram of the oxidant dosage of the present invention.
  • Figure 6 is a coloring time evaluation chart of the present invention.
  • Figure 7 is the ammonia nitrogen standard calibration curve
  • Figure 8 shows the evaluation of interfering substances.
  • Ammonia nitrogen standard solution (National Nonferrous Metals and Electronic Materials Analysis and Testing Center NH 3 -N) 1000mg/L, when used, dilute it with ultrapure water step by step to the required concentration; sodium salicylate (AR); sodium hydroxide (AR); potassium sodium tartrate (AR); sodium dichloroisocyanurate dihydrate (AR); sodium nitroprusside (AR);
  • All experimental water was ultrapure water obtained from an ultrapure water machine.
  • the reagents used in the present invention are all stable solid reagents.
  • the reaction mechanism of the present invention is as follows:
  • Salicylic acid colorimetric reaction mechanism Under alkaline conditions and the catalytic action of potassium nitrosoferricyanide, ammonia, ammonium ions and salicylate in water are reacted by hypochlorite ions to form the blue substance indigo. For phenol blue, use a spectrophotometer to measure the absorbance at a wavelength of 697nm to calculate the concentration of ammonia nitrogen in the water.
  • the main chromogenic agents of the salicylic acid method are salicylic acid and salicylate compounds. Since salicylic acid has low activity at normal temperature and pressure and is slightly soluble in water, it is usually the case if salicylic acid is used as the chromogenic agent. The usage will increase [7] . Therefore, a simpler salicylate with higher solubility, namely sodium salicylate, is selected as the color developer in the present invention.
  • the oxidant is selected as hypochlorite based on the reaction mechanism.
  • the common hypochlorite is sodium hypochlorite, but since sodium hypochlorite solution has poor stability and is easy to decompose, sodium dichloroisocyonurate is selected as a stable oxidant.
  • Cyanide salt plays a key role as a catalyst in the determination of ammonia nitrogen by the salicylic acid method.
  • sodium nitroprusside is one of the catalysts with better catalytic effect and stability among cyanide salts and is the most widely used. Therefore, sodium nitroprusside is selected in the present invention.
  • Sodium chloride is the best choice as a catalyst.
  • the overall chromophore is alkaline, but metal elements such as Fe, Mg and other metal ions in the water will form hydroxide precipitates under alkaline conditions, so a masking agent is indispensable.
  • Tartrate and citrate are both common and very effective masking agents. However, when using citrate as a masking agent, the amount of coexisting ions is larger, and of course the test requirements will be higher [8] . In comparison, Tartrate as a masking agent is more suitable for the system of this study, and potassium sodium tartrate is selected as the masking agent in the present invention.
  • the absorbance in the pH range of 11.54 to 1.97 is the best and most stable [9] , so in this system, the amount of sodium hydroxide is used to control the pH value of the system. .
  • Color developer and masking agent Weigh 50g salicylic acid into 100mL pure water, then add 160mL 2mol/L sodium hydroxide solution, stir until completely dissolved; then weigh 50g potassium sodium tartrate and dissolve in water, mix with the above solution Dilute to volume in a 1000mL volumetric flask and prepare a 1000mL solution.
  • Oxidizing agent Dilute sodium dichloroisocyanurate with water and 2mol/L sodium hydroxide solution into an oxidizing agent solution containing an effective chlorine concentration of 3.5g/L and a free base concentration of 0.75mol/L.
  • Catalyst Weigh 0.1g sodium nitroprusside and dissolve it in 10mL water to prepare a catalyst solution.
  • the final reagent formula was: 3.0g sodium salicylate, 0.1g sodium hydroxide, 0.1g potassium sodium tartrate, 0.05g sodium dichloroisocyanurate dihydrate, and 0.05g sodium nitroprusside.
  • Preparation of reagent package Put the components of each formula into a ceramic mortar and grind for 10 minutes to mix evenly and make the particles uniform, as shown in Figure 2. Pour 0.2g per package into an aluminum foil package of 50*60mm size, and use a sealing machine to vacuum seal to obtain an ammonia nitrogen detection reagent package. Each reagent package is suitable for 10mL water samples for ammonia nitrogen detection, as shown in Figure 3.
  • the dosage of sodium nitroprusside in the standard method is 10g/L.
  • a 1mg/L standard solution was used for evaluation, and the optimal concentration was around 12-20g/L.
  • the final sodium nitroprusside solid formula was 0.05g.
  • the concentration of the oxidizing agent is related to the concentration of the chromogen sodium salicylate. Therefore, determine the sodium salicylate formula content and control the variables to optimize the concentration of the oxidizing agent. As shown in Figure 5, the concentration of the oxidizing agent is in the range of 5 to 10g/L. Within, the absorbance reaches the maximum and is stable. After taking into account the weighing and the stability of the hypochlorite solution, it is determined that the amount of oxidant sodium dichloroisocyanurate added to the solid reagent formula is 0.05g.
  • the reagent package in this study can be used smoothly in normal indoor and outdoor environments and has no impact on the system at room temperature.
  • the temperature is too low (below 5°C)
  • the solubility of solid reagents is positively related to temperature, it is necessary to Hold the colorimetric reaction tube with your hand and shake it thoroughly until the reagent is completely dissolved. Extend the color development time slightly until the reaction is complete before testing.
  • the 0.03mg/L ammonia nitrogen standard solution was tested in parallel 8 times, and the standard deviation of the 8 results was calculated.
  • the ammonia nitrogen standard solution was gradually diluted to 1.00 mg/L, and the concentration values of five parallel samples were measured.
  • ammonia nitrogen detection solid reagent provided by the invention can meet the high requirements of portability and accuracy in water quality detection work, and has good application prospects.
  • This ammonia nitrogen detection solid reagent is simple, fast, and accurate, and is suitable for emergency rapid detection and analysis of groundwater, pipe network water, and wastewater.

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Abstract

一种用于氨氮检测的固体试剂及其检测方法，用于氨氮检测的固体试剂。包括下述质量份的组分：水杨酸钠2.4-3.6份、氢氧化钠0.08-0.12份，酒石酸钾钠0.08-0.12份，二氯异氰尿酸钠二水合物0.04-0.06份，硝普钠0.04-0.06份。该试剂适用于紫外分光光度仪来检测水中氨氮，优化了测试条件，与标准方法对比验证了检测准确性。结果表明，氨氮浓度范围在0.03～2.50mg/L的浓度范围内呈现很好的线性关系，加标回收率(n＝5)为95.0％～105.0％，检出限为0.01mg/L。该配方具有简便、快速、准确的特点，适用于地下水、管网水、以及废水的应急快速检测分析。

Description

一种用于氨氮检测的固体试剂及其检测方法 技术领域
本发明属于水质检测技术领域，具体涉及一种用于氨氮检测的固体试剂及其检测方法。
背景技术
水中氨氮是水质检测指标中重要的一项，是判断水体是否富营养化的重要指标之一，对生态造成影响的同时，危害生物的生存。氨氮指的是水体中呈游离态的氨和离子态的铵的统称。相比于铵根离子NH 4 +而言，氨NH 3对于生物来说更容易通过生物膜，因此氨氮的毒性主要指的是NH 3的毒性 [1]，其毒性与溶液的碱性呈正相关，当溶液pH或温度升高时。NH 3比例较高，反之NH 4 +比例较高 [2]。
针对于日常的氨氮检测，传统的水杨酸法 [3]和纳氏试剂法 [4]，存在显色时间较长、试剂的稳定性受温度影响较大、不稳定、检出上限较低、灵敏度较低等不足。施晓梅 [5]对于纳氏试剂法的研究中仍存在显色时间较长，稳定性较差，反应30min后显色不稳定，干扰因素较多的不足。娄红杰 [6]团队对于水杨酸法改进的研究虽然解决了很多问题，但仍然存在显色时间较长，达到30min等不足。此外基于目前市场上现有的便携式分光光度仪器的使用，对于环境水体来说大多数处于野外以及室外、河流湖泊岸边的采样检测环境，甚至是对于一些研究人员处于污水厂、管网、排水口、泵站等工作环境，对于水质检测的工作要求具有很高的便携度以及准确性。
发明公开
本发明的目的是提供一种用于氨氮检测的固体试剂。
本发明所提供的用于氨氮检测的固体试剂，包括下述质量份的组分：水杨酸钠2.4-3.6份、氢氧化钠0.08-0.12份，酒石酸钾钠0.08-0.12份，二氯异氰尿酸钠二水合物0.04-0.06份，硝普钠0.04-0.06份。
作为优选的，所述用于氨氮检测的固体试剂，包括下述质量份的组分：水杨酸钠3.0份、氢氧化钠0.1份，酒石酸钾钠0.1份，二氯异氰尿酸钠二水合物0.05份，硝普钠0.05份。
当然，所述用于氨氮检测的固体试剂也可以仅由下述质量份的组分组成：水杨酸钠3.0份、氢氧化钠0.1份，酒石酸钾钠0.1份，二氯异氰尿酸钠二水合物0.05份， 硝普钠0.05份。
根据本发明的一个具体实施例，所述用于氨氮检测的固体试剂可以试剂包的形式提供或商品化。所述用于氨氮检测的试剂包具体可由下述组分组成：水杨酸钠3.0g，氢氧化钠0.1g，酒石酸钾钠0.1g，二氯异氰尿酸钠二水合物0.05g，硝普钠0.05g。
本发明所提供的用于氨氮检测的固体试剂其反应机理为水杨酸比色法反应机理，具体如下：在碱性条件以及亚硝基铁氰化钾的催化作用下，水中氨、铵根离子与水杨酸盐被次氯酸根离子反应生成呈蓝色的物质靛酚蓝，用分光光度仪在波长697nm处测量吸光度，从而计算出水中氨氮的浓度。
本发明显色剂的选取：水杨酸法主要显色剂为水杨酸以及水杨酸盐类化合物，由于水杨酸在常温常压下活性较小，微溶于水，所以若使用水杨酸作为显色剂通常情况下会增加使用量 [7]。所以选取溶解度更高较为简单的水杨酸盐，即水杨酸钠作为本发明中的显色剂。
本发明氧化剂的选取：通过反应机理选取氧化剂为次氯酸盐。常见的次氯酸盐为次氯酸钠，但由于次氯酸钠溶液的稳定性较差，易分解，故选取二氯异腈脲酸钠作为稳定的氧化剂。
本发明催化剂的选取：氰络盐作为催化剂在水杨酸法测氨氮中有着关键的作用，其中硝普钠是氰络盐中催化效果以及稳定性较好、而且应用最为广泛的催化剂之一，所以本发明中选取硝普钠作为催化剂为最佳选择。
本发明掩蔽剂的选取：整体的显色体呈碱性，但水体中金属元素例如Fe、Mg等金属离子在碱性条件下会形成氢氧化物沉淀，所以掩蔽剂不可或缺。酒石酸盐与柠檬酸盐都是常见并且效果很好的掩蔽剂，但使用柠檬酸盐作为掩蔽剂时，共存离子量较大，固然测试要求的条件就会更高 [8]，相比之下酒石酸盐作为掩蔽剂更适合本研究的体系，选取酒石酸钾钠作为本研究的掩蔽剂。
本发明体系pH值的控制：在硝普钠催化水杨酸盐体系中，pH值在11.54～1.97范围内的吸光度最佳，并且最稳定，所以在该体系中，用氢氧化钠的量来控制体系的pH值。
本发明中所述用于氨氮检测的固体试剂具体可用于水质氨氮检测。
进一步的，所述用于氨氮检测的固体试剂适用于地下水、管网水、以及废水的应急快速检测分析
本发明还提供了利用上述用于氨氮检测的固体试剂进行水质氨氮检测的方法。
本发明所提供的方法包括下述步骤：
(1)将所述用于氨氮检测的固体试剂溶解于待测水样中，使所述固体试剂与待测水样反应；
(2)通过紫外分光光度仪测量步骤(1)所得溶液的吸光值并计算出氨氮含量。
上述方法步骤(1)中，当所述用于氨氮检测的固体试剂采用0.2g的试剂包时，每个试剂包适用于10mL水样的氨氮检测。
上述方法步骤(1)中，所述反应的时间(显色时间)不低于10min。在不低于5℃的室内外环境下，反应时间具体可为10min。
上述方法步骤(1)中，若所述待测水样的pH值大于9.0或小于5.0，在检测前还需将pH值调整到7.0。
上述方法步骤(2)中，所述紫外分光光度仪在697nm波长处测定吸光度。
上述方法可用于检测氨氮浓度范围在0.03～2.50mg/L的水样。若待测水样中氨氮浓度超出此范围，可以适当稀释后再进行检测。
与现有技术相比，本发明具有如下有益效果：
本发明提供的氨氮检测固体试剂可以满足水质检测工作对于便携度以及准确性的高要求，具有很好的应用前景。除此之外，相比进口的氨氮检测试剂价格昂贵，订购周期较长，运输时间较长，且稳定性较差，对温度以及使用过程较敏感，本发明的氨氮检测固体试剂在这方面同样具有很好的发展前景。该配方具有简便、快速、准确的特点，适用于地下水、管网水、以及废水的应急快速检测分析。
附图说明
图1为HJ 536-2009方法测氨氮标准曲线；
图2为研磨之前的固体试剂(左图)和研磨后的试剂粉末(右图)；
图3为本发明提供的氨氮检测试剂包；
图4为本发明中硝普钠用量评价图；
图5为本发明氧化剂用量评价图；
图6为本发明显色时间评价图；
图7为氨氮标准校正曲线；
图8为干扰物质评价。
实施发明的最佳方式
下面结合具体实施例对本发明作进一步阐述，但本发明并不限于以下实施例。所 述方法如无特别说明均为常规方法。所述原材料如无特别说明均能从公开商业途径获得。
下述实施例中使用的主要仪器如下：
梅特勒UV5紫外分光光度仪；带盖比色管(15mL)；石英比色皿(1cm)；eppendorf移液器(1mL、5mL)；电子天平(万分之一)；力元超纯水机。
下述实施例中使用的主要试剂如下：
氨氮标准溶液(国家有色金属及电子材料分析测试中心NH 3-N)1000mg/L，使用时根据需要逐级用超纯水稀释成所需的浓度；水杨酸钠(AR)；氢氧化钠(AR)；酒石酸钾钠(AR)；二氯异氰尿酸钠二水合物(AR)；硝普钠(AR)；
实验用水均为由超纯水机得到的超纯水。
为了满足试剂包的制作要求，本发明所用试剂均为稳定的固体试剂。
本发明的反应机理如下：
水杨酸比色法反应机理：在碱性条件以及亚硝基铁氰化钾的催化作用下，水中氨、铵根离子与水杨酸盐被次氯酸根离子反应生成呈蓝色的物质靛酚蓝，用分光光度仪在波长697nm处测量吸光度，从而计算出水中氨氮的浓度。
本发明固体显色试剂中显色剂的选取：
水杨酸法主要显色剂为水杨酸以及水杨酸盐类化合物，由于水杨酸在常温常压下活性较小，微溶于水，所以若使用水杨酸作为显色剂通常情况下会增加使用量 [7]。所以选取溶解度更高较为简单的水杨酸盐，即水杨酸钠作为本发明中的显色剂。
本发明固体显色试剂中氧化剂的选取：
通过反应机理选取氧化剂为次氯酸盐。常见的次氯酸盐为次氯酸钠，但由于次氯酸钠溶液的稳定性较差，易分解，故选取二氯异腈脲酸钠作为稳定的氧化剂。
本发明固体显色试剂中催化剂的选取：
氰络盐作为催化剂在水杨酸法测氨氮中有着关键的作用，其中硝普钠是氰络盐中催化效果以及稳定性较好、而且应用最为广泛的催化剂之一，所以本发明中选取硝普钠作为催化剂为最佳选择。
本发明固体显色试剂中掩蔽剂的选取：
整体的显色体呈碱性，但水体中金属元素例如Fe、Mg等金属离子在碱性条件下会形成氢氧化物沉淀，所以掩蔽剂不可或缺。酒石酸盐与柠檬酸盐都是常见并且效果很好的掩蔽剂，但使用柠檬酸盐作为掩蔽剂时，共存离子量较大，固然测试要求的条件就会更高 [8]，相比之下酒石酸盐作为掩蔽剂更适合本研究的体系，选取酒石酸钾钠 作为本发明中的掩蔽剂。
pH值的控制：
在硝普钠催化水杨酸盐体系中，pH值在11.54～1.97范围内的吸光度最佳，并且最稳定 [9]，所以在该体系中，用氢氧化钠的量来控制体系的pH值。
实施例1、用于氨氮检测的固体试剂的配制
1、实验过程
首先按照HJ 536-2009《水质氨氮的测定水杨酸分光光度法》 [3]的标准配制相应的试剂。
显色剂及掩蔽剂：称取50g水杨酸于100mL纯水中，再加入160mL 2mol/L的氢氧化钠溶液，搅拌至完全溶解；再称取50g酒石酸钾钠溶于水中，与上述溶液定容于1000mL容量瓶中，配制成1000mL溶液。
氧化剂：将二氯异腈脲酸钠用水和2mol/L的氢氧化钠溶液稀释成含有效氯浓度3.5g/L，游离碱浓度0.75mol/L的氧化剂溶液。
催化剂：称取0.1g硝普钠溶于10mL水中配制成催化剂溶液。
将氨氮标准溶液配制成8.00mL，浓度分别为0.00、0.20、0.40、0.60、0.80、1.00mg/L的标准溶液与10mL比色管中，再分别加入按照之前步骤配制好的1.00mL显色剂和两滴催化剂溶液，混合均匀。再分别滴入2滴氧化剂溶液并混匀，分别加纯水至标线后充分混匀。显色60min后在697nm波长处，用10mm比色皿，以纯水为参比用梅特勒UV5紫外分光光度仪分别测其光度，做出浓度与吸光度对应的标准曲线，如表1和图1所示。
表1 HJ 536-2009方法测氨氮浓度对应吸光度表
Figure PCTCN2022126386-appb-000001
根据试剂的选取更改配方成分并通过一些方法进行实验，从而得到每个配方成分最佳的比例，详见2.2。最终以试剂包的形式呈现和使用。
2、实验结果。
经过评价实验，最终得到的试剂配方为：水杨酸钠3.0g，氢氧化钠0.1g，酒石酸钾钠0.1g，二氯异氰尿酸钠二水合物0.05g，硝普钠0.05g。
试剂包的制作：将各配方的组分分别放入陶瓷研钵中研磨10min混合均匀并且颗粒均匀，如图2所示。按照每包0.2g倒入50*60mm规格的铝箔包装中，并用封口机 进行抽真空封口，得到氨氮检测试剂包，每个试剂包适用于10mL的水样进行氨氮检测，如图3所示。
2.1最大吸收波长
取浓度为1.00mg/L的氨氮标准溶液根据HJ 536-2009《水质氨氮的测定水杨酸分光光度法》 [3]方法显色，在波长300-800nm范围内扫描。在697nm处有最大吸收峰。取浓度为2.00mg/L的氨氮标准溶液用本发明中试剂包方式显色同样在波长300-800nm范围内扫描。同样在697nm处有最大吸收峰。
2.2主要试剂成分用量
在HJ 536-2009《水质氨氮的测定水杨酸分光光度法》 [3]标准方法中水杨酸用量为50g/L，由于本研究中量程为标准方法的2.5倍，所以水杨酸钠溶液的使用量最初优化为150g/L。从溶液改为固体试剂得到水杨酸固体配方为3.0g试剂为最佳配比。
对于催化剂和氧化剂采取控制变量逐渐增加含量的方法探索最佳的配方含量。
在标准方法中硝普钠的用量为10g/L，结合本研究进行固体试剂硝普钠的优化实验中，用1mg/L的标液用于评价，最佳浓度为12-20g/L左右浓度，如图4所示。综合称量、催化效果等条件最终得到硝普钠固体配方为0.05g。
氧化剂的浓度与显色剂水杨酸钠的浓度相关联，所以，确定水杨酸钠配方含量，控制变量优化氧化剂的浓度，如图5所示，氧化剂的浓度在5～10g/L的范围内，吸光度达到最大且稳定，同时考虑到称量以及次氯酸盐溶液的稳定性后，确定固体试剂配方中加入氧化剂二氯异氰尿酸钠的量为0.05g。
对于该显色体系调整pH值在11.54～11.97范围内，并综合各条件，选取氢氧化钠0.1g作为固体试剂配方的含量。
2.3显色时间的影响
本研究中的试剂包在正常室内外环境可顺利进行，在室温环境下对体系没有影响，温度过低时(5℃以下)由于固体试剂的溶解度与温度成正相关，所以在这种环境下需要用手握住比色反应管，充分震荡至试剂完全溶解后，显色时间稍延长一些至充分反应后再进行测试。
在实验条件下，分别选取低浓度0.5mg/L和高浓度2mg/L的氨氮标准液作为样品，加入固体试剂后每隔一段时间进行一次吸光度测定，结果如图6所示，体系显色10min后吸光度开始稳定并保持稳定在180min以上，故选取显色时间为10min。
2.4标准曲线以及方法的检出限
准确按比例稀释1000mg/L的氨氮标准溶液，配制0.10、0.25、0.50、1.00、1.50、 2.00、2.50mg/L浓度的样品10mL，按照试剂包的使用方法进行显色反应和测试吸光度，并且分别以氨氮浓度和吸光度为横坐标和纵坐标制作标准校正曲线，如图7所示。测试结果表明，氨氮的质量浓度在0.10～2.50mg/L范围内符合朗伯比尔定律，线性回归方程为y＝1.08x+0.04，线性相关系数R＝0.999，具有很好的线性相关度。
预估检出限EDL＝0.010abs的吸光度变化相对应的浓度变化，为0.01mg/L按照实验方法对0.03mg/L的氨氮标准溶液平行测试8次，并且计算这8次结果的标准偏差，按照MDL＝t(n-1,0.99)*S计算出方法检出限为0.01mg/L。
2.5共存离子以及干扰因素的影响
在本研究中评价了几种主要的干扰物质Ca 2+、Cl -、NO 3 -，对于测量浓度范围内的相对误差均不超过5％的程度，如图8所示。在1.00mg/L的氨氮标准溶液中Ca 2+在8g/L以上时出现吸光度很大程度的提升，并且出现白色沉淀增加，是由于掩蔽剂与氢氧根离子与Ca 2+离子形成的沉淀物质，当沉淀达到一定程度后对检测光源的散射影响了吸光度，从而导致吸光度增加。而其余两种干扰物质均未出现较大的影响。
对于pH较大或较小的样品，用1N浓度的氢氧化钠溶液或盐酸溶液对样品进行预处理工作，pH调整到7.0左右。
2.6不同水样加标回收率
取一组附近管网处水样进行氨氮含量的检测以及加标回收率的实验，氨氮含量过高的水样进行稀释预处理，加标量为0.2mL，5mg/L氨氮标液，实验结果如表2所示，回收率为95.0％～105％。
表2加标回收实验结果
Figure PCTCN2022126386-appb-000002
2.7精密度分析
逐级稀释氨氮标准溶液至1.00mg/L，测定5个平行样品的浓度值，精密度分析结果如表3所示，可知，方法的精密度(RSD，n＝5)为0.470％。
表3精密度分析结果
Figure PCTCN2022126386-appb-000003
本研究中，通过实验以及反应机理的分析得到一种新的用于紫外分光光度仪的氨氮固体检测试剂包配方，适用于水中氨氮的快速监测，从显色稳定性以及检测准确定来看都达到了很高的水平，同时解决了以往的检测试剂便携度低、显色时间较长、试剂稳定性低、检出上限较低、灵敏度较低等问题。本方法与实验室标准方法相比较无显著差异，满足于日常检测使用要求。此方法经济、操作简便以及便携，适用于地下水、管网水、以及废水的应急快速检测分析。
参考文献
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工业应用
本发明提供的氨氮检测固体试剂可以满足水质检测工作对于便携度以及准确性的高要求，具有很好的应用前景。该氨氮检测固体试剂具有简便、快速、准确的特点，适用于地下水、管网水、以及废水的应急快速检测分析。

Claims (10)

  1. 一种用于氨氮检测的固体试剂，包括下述质量份的组分：水杨酸钠2.4-3.6份、氢氧化钠0.08-0.12份，酒石酸钾钠0.08-0.12份，二氯异氰尿酸钠二水合物0.04-0.06份，硝普钠0.04-0.06份。
  2. 根据权利要求1所述的固体试剂，其特征在于：所述用于氨氮检测的固体试剂，包括下述质量份的组分：水杨酸钠3.0份、氢氧化钠0.1份，酒石酸钾钠0.1份，二氯异氰尿酸钠二水合物0.05份，硝普钠0.05份。
  3. 根据权利要求2所述的固体试剂，其特征在于：所述用于氨氮检测的固体试剂为试剂包，所述试剂包由下述组分组成：水杨酸钠3.0g，氢氧化钠0.1g，酒石酸钾钠0.1g，二氯异氰尿酸钠二水合物0.05g，硝普钠0.05g。
  4. 权利要求1-3中任一项所述的用于水质氨氮检测固体试剂在水质氨氮检测中的应用。
  5. 根据权利要求4所述的应用，其特征在于：所述用于氨氮检测的固体试剂适用于地下水、管网水、以及废水的应急快速检测分析。
  6. 一种用于水质氨氮检测的方法，是利用权利要求1-3中任一项所述的用于水质氨氮检测固体试剂，包括如下步骤：
    (1)将所述用于氨氮检测的固体试剂溶解于待测水样中，使所述固体试剂与待测水样反应；
    (2)通过紫外分光光度仪测量步骤(1)所得溶液的吸光度值计算出氨氮含量。
  7. 根据权利要求6所述的方法，其特征在于：所述步骤(1)中，所述用于氨氮检测的固体试剂为权利要求3所述的试剂包，每个所述试剂包适用于10mL水样的氨氮检测。
  8. 根据权利要求6或7所述的方法，其特征在于：所述步骤(1)中，所述反应的时间不低于10min。
  9. 根据权利要求6-8中任一项所述的方法，其特征在于：所述步骤(1)中，所述待测水样的pH值大于9.0或小于5.0，在检测前还需将pH值调整到7.0。
  10. 根据权利要求6-8中任一项所述的方法，其特征在于：所述步骤(2)中，所述紫外分光光度仪在697nm波长处测定吸光度。
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