首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
副品红褪色光度法测定海水中亚硝酸根   总被引:2,自引:0,他引:2  
潘志信 《分析化学》2000,28(11):1447-1447
1 引  言亚硝酸根是公认的致癌物质。水体和食品中的亚硝酸根受到人们的普遍关注。测定亚硝酸根的方法也在不断改进。光度法测定亚硝酸根已有许多报道。其中Griess法较为常用。本文研究表明 ,在pH 2 .0~ 3.5缓冲溶液中 ,副品红与NO-2 作用而明显褪色 ,据此建立了测定亚硝酸根的新方法。该方法较Griess法简便、准确、无毒 ;较甲基紫褪色光度法灵敏度更高 ,检测限更低。2 实验部分2 1 试剂及仪器 亚硝酸根标准溶液按文献用分析纯NaNO2 配制 ,2 0 0mg L储备液。 4mg L ,0 5mg L工作液现用现配。pH 2 .…  相似文献   

2.
对氨基苯甲酸荧光猝灭法测定痕量亚硝酸根   总被引:1,自引:0,他引:1  
亚硝酸根广泛存在于土壤、天然水、食品等物质中,亚硝酸根被人体吸收后,可使体内正常的血红蛋白氧化而失去携氧能力,与胺类及酰胺类化合物反应生成致癌性的亚硝胺类物质,亚硝酸根是环境和食品等检测的重要项目之一。因此,建立高灵敏、高选择性的测定亚硝酸根方法十分重要。由于分子荧光光度法具有灵敏度高,干扰少,试剂低毒等特点,引起了广泛关注。但已报道的此类测定方法除加入荧光化合物外,还需加入其它辅助试剂,使试验相对复杂。文献方法用亚硝酸根直接与藏红T在盐酸介质中发生重氮化反应测定了亚硝酸根。  相似文献   

3.
荧光猝灭法测定痕量亚硝酸根   总被引:18,自引:0,他引:18  
苑宝玲  林清赞 《分析化学》2000,28(6):692-695
研究了用荧光猝灭法测定了亚硝酸根。本方法是基于亚硝酸根与碘化钾反应生成了单质碘,碘可以使2’,7’0二氯荧光素(DCF)发生荧光猝灭,从而间接测定亚硝酯根。亚硝酸根浓度在10 ̄120μg/L范围内,荧光强度差值与亚硝酸根浓度呈线性关系。检测限为5.6μg/L。本法简便、灵敏度较高,已用于合成样和分析纯试剂中亚硝酸根的测定。  相似文献   

4.
酪氨酸作试剂荧光光度法测定亚硝酸根   总被引:6,自引:0,他引:6  
亚硝酸盐广泛存在于土壤、食品及天然水中 ,是水体中氮循环的重要中间物。亚硝酸盐可引起急性中毒 ,还可以与仲胺和酰胺等结合成致癌的亚硝胺化合物 ,是造成环境污染的主要原因之一。因此 ,亚硝酸盐的含量是环境监测和食品分析的重要指标。荧光法测定亚硝酸根常用的试剂是 2 ,3 二氨基萘[1] ,但需用有机溶剂萃取 ,操作繁琐 ,而且由于试剂本身有毒 ,易造成二次污染。近年来有人报道了荧光猝灭法测定亚硝酸根[2 ,3] 。本文以亚硝酸根与酪氨酸反应产物在碱性介质中呈现强的荧光 ,其激发波长和发射波长分别为 31 8.0nm和 398.4nm ,建立了水…  相似文献   

5.
反相流动注射光度法测定微量亚硝酸根   总被引:4,自引:0,他引:4  
訾言勤  陈立国 《分析化学》2000,10(3):395-395
1引言亚硝酸根是环境中有害的物质,现行的标准分析方法需用对人体有害的试剂α-萘胺。本文采用流动注射分析法,研究了酸性品红与亚硝酸根的反应,优化了实验条件,根据自研微机化流动注射分析仪能准确控制时间的特点,利用非平衡法建立了测定微量亚硝酸根的快速分析新方法。线性范围为0-5.0mg/L,分析速度每小时测定36次。不用分离直接测定煤矿塌陷湖水、鱼塘水、电厂废水和地下水中的亚硝酸根均获得满意结果。2实验部分2.1仪器与试剂MFIA型流动注射分析仪(自研),DMS-200型紫外可见分光光度计(Varian公司)。亚硝酸根标准溶液…  相似文献   

6.
催化荧光法测定痕量亚硝酸根和硝酸根   总被引:9,自引:0,他引:9  
亚硝酸盐广泛存在于土壤、天然水、食品等物质中,其易于仲胺、酰胺等反应,生成强烈致癌的亚硝胺化合物,是水污染的指标之一.亚硝酸根的测定通常采用Griess比色法,近年来又报道了极谱法和动力学法.试验发现,在稀磷酸溶液中.亚硝酸根对溴酸钾氧比罗丹明6G的反应有很强的催化作用,据此建立了测定痕量亚硝酸根的催化荧光分析方法,硝酸根可用锌粉还原至亚硝酸根进行测定.本法用于雨水中痕量亚硝酸根和硝酸根的测定,得到了满意结果.  相似文献   

7.
催化光度法测定痕量亚硝酸根   总被引:17,自引:0,他引:17  
张克忠  冯尚彩 《分析化学》1998,26(4):494-494
1引言近年来,有关催化光度法测定亚硝酸根的方法已有若干报道。笔者在前人进行荧光测定的基础上,研究了在稀磷酸介质中,亚硝酸根对溴酸钾氧化中性红的强催化作用,提出了以溴酸钾为氧化剂,中性红为还原剂测定亚硝酸根的催化光度法,结果具有很高的灵敏度和较好的选择性。用于地面水及地下水中NO-2的测定,结果满意。2实验部分2.1仪器与试剂753WB紫外可见分光光度计(上海光学仪器厂);电热恒温水浴锅。亚硝酸根标准溶液:由亚硝酸钠配成1.00g/L亚硝酸根储备液;本溶液贮存于棕色瓶中,每升加入2mL三氯甲烷和两…  相似文献   

8.
1 引言 亚硝酸根是致癌的重要物质,它广泛存在于水体及食品中.因此,痕量亚硝酸根的测定方法研究一直受到重视.现行亚硝酸根测定的标准方法尚存在灵敏度不高和引入致癌物质之不足.催化动力学分析法具有灵敏度高、方法简单、使用试剂量小等特点,作者实验观察到,在稀磷酸介质中溴酸钾氧化1,5-二(2-羟基-5-磺酸基苯)-3-氰基甲 (DSPCF)的反应受到痕量亚硝酸根的强烈催化加速,据此建立了一个测定痕量亚硝酸根的催化光度法.方法灵敏度高,线性范围宽.  相似文献   

9.
树脂相分光光度法测定痕量亚硝酸根   总被引:6,自引:0,他引:6  
刘峥  曾嵘 《分析化学》2001,29(4):492-492
1  引    言K.Horita利用亚硝酸根与对氨基苯磺酸反应形成重氮盐,然后与酚类化合物发生偶联反应生成有色偶联产物,再用萘-碘化十四烷基二甲基铵(TDBA-I-)吸附剂进行富集获得了测定亚硝酸根的满意结果。本文利用国产717强碱性阴离子交换树脂,吸附对氨基苯磺酸甲萘胺体系形成的偶氮染料,建立了树脂相分光光度法测定亚硝酸根的新方法。并用于实际样品的测定,结果满意。2  实验部分2.1  试剂和仪器  亚硝酸根标准溶液:1 g/L(储备液)、1 mg/L(工作液),并贮存于棕色瓶中。对氨基苯磺…  相似文献   

10.
罗丹明3GO荧光猝灭法测定微量亚硝酸根   总被引:11,自引:0,他引:11  
董存智 《分析化学》2002,30(11):1407-1407
1 引  言亚硝酸根与芳胺或苯甲胺反应因生成致癌物质亚硝胺而引起广泛的关注。测定亚硝酸根的方法除经典的Griess法外还有分光光度法、荧光法、催化动力学法等 ,但利用罗丹明 3GO与亚硝酸根发生的荧光熄灭法测定亚硝酸根的方法尚未见报道。本研究发现 ,在盐酸介质中 ,亚硝酸根的加入使罗丹明 3GO荧光强度明显降低 ,其降低程度与亚硝酸根的加入量间存在着良好的线性关系 ,从而建立了用罗丹明 3GO荧光熄灭法测定亚硝酸根的新方法。方法操作简单 ,灵敏度高 ,重现性好 ,可直接测定水样中的亚硝酸根。2 实验部分2 .1 仪器和试剂…  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

14.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

15.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

16.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

17.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

18.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

19.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

20.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号