土壤硝酸盐测定.doc

Application NoteAN 5206Date issued: 2000-03-06 Last revised:DETERMINATION OF NITRATE IN 2M KCl SOIL EXTRACTS BY FIASTAR 5000使用FIASTAR 5000测定2M KCl土壤浸出样中的硝酸盐1. Scope and field of application应用范围This Application Note describes a method for determination of nitrate in soil extracts in the following range: 本简报描述方法用于测定土壤浸出液中硝酸盐，测定范围：0.1-5 mg/l NO3-N in the extract (40 ml 样品圈)，线性定标0.1-5 mg/l NO3-N ，(40 ml 样品圈), 线性定标2. Principle of the method测试原理Nitrate in the soil sample is extracted by 2M KCl. The suspension is centrifuged and filtered and can after this treatment be introduced in a flow injection system. The chemical principle for determination of nitrate is reduction to nitrite in a cadmium reductor. See AN 5201 for details. The described method gives the sum of nitrite and nitrate originally present in the extract. However, the original concentration of nitrite is in most cases negligible in comparison with the nitrate concentration. 使用2M KCl溶液浸出土壤样品中的硝酸盐。

浸出悬浮液离心并过滤后可使用流动注射系统进行分析测试硝酸盐的原理是使用镉柱（还原剂）将硝酸盐还原成亚硝酸盐，详细信息参见简报AN5201本方法从本质上讲测试的是土壤浸出液中硝酸盐和亚硝酸盐的总和，但是，同浸出液中含有的硝酸盐量相比，所含的亚硝酸盐可忽略不计3. Reagents试剂Before using any chemicals refer to adequate manuals or safety data sheets approved by your local authorities. If not stated otherwise, only reagents of recognized analytical grade and water according to grade 1 of ISO 3696 shall be used.在使用任何化学试剂之前，请参考当地政府颁发的准许使用手册和安全数据标准如果没有特殊说明，本简报所允许使用的试剂为分析级，配置试剂所用的水应符合ISO3696标准的1级水3.1 Sulphanilamide (4-aminobenzenesullfonamide), C6H8N2O2S 4-氨基苯磺酸C6H8N2O2S3.2 N-(1-naphtyl)-Ethylene Diamine Dihydrochloride , C12H14N2 x 2 HCl1-萘胺盐酸盐，C12H14N2 x 2 HCl3.3 Hydrochloric acid; HCl w=37% 盐酸, HCl 37%3.4 Sodium Nitrite, NaNO2, dried to constant mass at 150 °C亚硝酸钠，NaNO2，在105°C干燥至恒重3.5 Sodium Nitrate, NaNO3, dried to constant mass at 105 °C硝酸钠，NaNO3，在105°C干燥至恒重3.6 Ammonium Chloride, NH4Cl, dried to constant mass at 105 °C 氯化铵，NH4Cl，在105°C干燥至恒重3.7 Ammonia, NH4OH氨水，NH4OH3.8 Potassium Chloride, KCl氯化钾，KCl 3.9 2M Potassium chloride, KCl2M 氯化钾溶液，KClIn a suitable container, dissolve Potassium chloride in water. For preparation of this solution, see table. 采用合适的容器，将氯化钾溶解于水中配制2M的氯化钾溶液，配方如下表：VolumeKCl1 l(1升)149.1 g5 l(5升)745.5 g10 l(10升)1491 g20 l(20升)2982 g3.10 Carrier solution, 2M KCl 载液，2M KCl溶液See 3.9 见3.93.11 Ammonium Chloride buffer pH 8.5, reagent = 氯化铵缓冲液, pH 8.5，试剂=Dissolve 85 g Ammonium Chloride, NH4Cl in 500 ml of distilled water. Allow the solution to reach room temperature. Add Ammonia, NH4OH (about 12 ml) to reach a pH of 8.5. Mix and dilute to 1000 ml with distilled water.将85g氯化铵溶于500ml水中。

将溶液平衡至室温加入氨水(约12ml)，调节pH到8.5，然后将溶液充分混合，用蒸馏水稀释至1000ml3.12 Sulphanilamide reagent == 氨基苯磺酸试剂==In a volumetric flask of nominal capacity 500 ml, dissolve 5g Sulphanilamide in 250 ml distilled water. Add 25 ml concentrated Hydrochloric acid and mix carefully. Dilute to volume with distilled water. Transfer the content of the flask to the reagent bottle labelled ==.This reagent is stable for several months.Note! For the preparation of this reagent 50 ml of Phosphoric acid may be used instead of Hydrochloric acid将5g氨基苯磺酸溶解在250ml蒸馏水中，加25ml浓盐酸，仔细搅拌混合后，将溶液转移至500ml的容量瓶中，用蒸馏水定容。

然后将溶液转移至标号为==的试剂瓶中此试剂可稳定保存几个月注：配制此试剂可使用50ml磷酸代替盐酸3.13 NED reagent ===NED 萘胺盐酸盐试剂===In a volumetric flask of nominal capacity 500 ml, dissolve 0.5g N-(1-naphtyl)-Ethylene Diamine Dihydrochloride in approximately 250 ml of distilled water. Make up to volume with distilled water. Transfer the content to the reagent bottle labelled ===.This solution should be freshly prepared every week.将0.5g1-萘胺盐酸盐C10H9N.3H2O.HCl溶于250ml蒸馏水，溶液转移至500ml容量瓶中，用蒸馏水定容将配制的溶液转移至标号为===的试剂瓶中此溶液应每星期新鲜配制3.14 Stock standard solution, 1000 mg/l NO3-N 标准储备液，1000 mg/l NO3-NIn a volumetric flask of nominal capacity 1000 ml, dissolve 6.068 g Sodium Nitrate and dilute to volume with distilled water.The stock standard is stable for at least 3 months.将6.608g硝酸钠溶解于蒸馏水水中，将溶液转移至1000ml的容量瓶中，用蒸馏水定容至刻度。

此储备液可稳定保存3个月3.15 Interim stock standard 20 mg/l NO3-N临时储备液 20 mg/l NO3-NPipette 10 ml of the stock standard solution into a 500 ml volumetric flask and dilute to volume with 2 M KCl.This solution should be prepared fresh daily.取标准储备液10ml转移至500ml的容量瓶中，然后用2 M KCl溶液稀释至刻度此溶液应每天新鲜配制3.16 Calibrating solutions 定标系列标准溶液The calibrating solutions are prepared by diluting the solution described in 3.13 with 2 M KCl. At least five calibration standards per working range are recommended使用临时储备液，根据下表用2M KCl溶液配制定标系溶液。

每个工作范围至少需配制5个标准溶液Working range 0.1-5 mg/l NO3-N工作范围0.1-5 mg/l NO3-NNO3-N concentrationmg/lNO3-N浓度mg/lVolume interim standard (3.15)ml临时储备液体积 mlFinal volumeml最终体积，ml0-1000.10.51000.52.510015100210100525100The calibrating solutions should be prepared fresh daily.定标溶液应每天新鲜配制4. Apparatus仪器和设备Usual laboratory apparatus and 常用实验室容器。