Galil Mansour S Abdul, Kumar M S Yogendra, Nagendrappa G
Department of Studies in Chemistry, University of Mysore, Manasagangotri, Mysore 570 006, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 May;67(1):76-82. doi: 10.1016/j.saa.2006.06.026. Epub 2006 Jun 30.
A rapid, simple, and most economical spectrophotometric method was proposed for the determination of nitrite in various water samples, soil samples, and roots of leguminous plants. The method is based on decolorizing effect of nitrite on complex formed between hydrogen peroxide and vanadate in acidic medium. The decolorization of that complex by nitrite was exploited to monitor the reaction spectrophotometrically at 470 nm. The method was optimized for effect of concentrations of ammonium metavanadate, hydrogen peroxide, various acids, concentrations of sulphuric acid, order of reagents addition and color stability. The color of the complex was found to be stable for about 2 days, and the stability constant of the complex was also calculated by modified Job's method. The linearity range of the calibration graph was over 6.67-66.7 microg ml(-1) of nitrite with molar absorptivity, 0.276 x 10(3) mol(-1) l cm(-1) and Sandell's sensitivity, 0.1667 microg cm(-2). The method was applied successfully for the determination of nitrite in soil samples, various wastewater samples and roots of leguminous plants.
提出了一种快速、简便且极为经济的分光光度法，用于测定各类水样、土壤样品以及豆科植物根系中的亚硝酸盐。该方法基于在酸性介质中亚硝酸盐对过氧化氢与钒酸盐形成的络合物的褪色作用。利用亚硝酸盐使该络合物褪色这一现象，在470 nm处通过分光光度法监测反应。对偏钒酸铵、过氧化氢、各种酸的浓度、硫酸浓度、试剂添加顺序以及颜色稳定性的影响进行了方法优化。发现该络合物的颜色在约2天内稳定，并且还通过改进的乔布法计算了该络合物的稳定常数。校准曲线的线性范围为亚硝酸盐浓度在6.67 - 66.7 μg ml⁻¹之间，摩尔吸光系数为0.276×10³ mol⁻¹ l cm⁻¹，桑德尔灵敏度为0.1667 μg cm⁻²。该方法成功应用于土壤样品、各类废水样品以及豆科植物根系中亚硝酸盐的测定。
