A flow-injection spectrophotometric method for nitrate and nitrite,determination through nitric oxide generation
A flow-injection spectrophotometric method for nitrate and nitrite,determination through nitric oxide generation
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DOI：
10.1016/s0308-8146(02)00508-3
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发表时间：
2003-04-01
期刊：
影响因子：
8.8
通讯作者：
Rath, S
中科院分区：
文献类型：
--
作者：
Andrade, R;Viana, CO;Rath, S
提出了一种流动注射分光光度法测定食品中亚硝酸盐和硝酸盐的新方法。该方法是基于亚硝酸盐和硝酸盐还原成一氧化氮，随后与铁（11）和硫氰酸盐在酸性介质中反应，形成FeSCNNO+。该配合物的吸光度与亚硝酸盐和硝酸盐浓度成正比，最大吸光度在460 nm处。NO的生成分为两个阶段：(1)在镉铜还原柱中将硝酸盐还原为亚硝酸盐；(2)在硫酸介质中将亚硝酸盐还原为NO。考察了试剂浓度和多种参数对反应的影响。亚硝酸盐和硝酸盐的测定范围分别为0.30 ~ 3.00 mg l和1.00 ~ 10.00 mg l（-1）。分析取样时间为30-40 h(-1)，考虑样品为5.0 g，该方法的硝酸盐和亚硝酸盐的检出限分别为20和13 mg kg（-1）。用该方法测定了蔬菜和肉制品中的亚硝酸盐和硝酸盐。该方法精密度和准确度与参考分光光度法（AOAC测定食品中硝酸盐的官方参考方法）相当。(C) 2002 Elsevier Science Ltd.版权所有。
A flow injection method with novel spectrophotometric detection for the determination of nitrite and nitrate in foodstuffs is presented. The method is based on the reduction of nitrite and nitrate to nitric oxide, with subsequent reaction with iron (11) and thiocyanate in an acid medium, forming FeSCNNO+. The absorbance of the complex, with a maximum at 460 nm, is proportional to the nitrite and nitrate concentrations. The NO is generated in two stages: (1) reduction of nitrate to nitrite in a cadmium copper reductor column and (2) reduction of the nitrite to NO in a sulfuric acid medium. The influence of reagent concentrations and manifold parameters were evaluated. Nitrite and nitrate can be determined in the range of 0.30-3.00 and 1.00-10.00 mg l(-1), respectively. The sampling rate of analyses was 30-40 h(-1) and, considering a sample of 5.0 g, the determination limit of the method was 20 and 13 mg kg(-1) of nitrate and nitrite, respectively. Nitrite and nitrate were determined in vegetables and meat products by the proposed method. The precision and accuracy of the proposed method were comparable to those of the reference spectrophotometric method (official AOAC reference method for the determination of nitrate in foodstuffs). (C) 2002 Elsevier Science Ltd. All rights reserved.