School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, China.
Talanta. 2004 Jan 9;62(1):97-101. doi: 10.1016/S0039-9140(03)00421-1.
A new flow injection catalytic spectrophotometric method is proposed for the simultaneous determination of nitrite and nitrate based on the catalytic effect of nitrite on the redox reaction between crystal violet and potassium bromate in phosphoric acid medium and nitrate being on-line reduced to nitrite with a cadmium-coated zinc reduction column. The redox reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of crystal violet at the maximum absorption wavelength of 610nm. A technique of inserting a reduction column into sampling loop is adopted and the flow injection system produces a signal with a shoulder. The height of shoulder in the ascending part of the peak corresponds to the nitrite concentration and the maximum of the peak corresponds to nitrate plus nitrite. The detection limits are 0.3ngml(-1) for nitrite and 1.0ngml(-1) for the nitrate. Up to 32 samples can be analyzed per hour with a relative standard deviation of less than 2%. The method has been successfully applied for the simultaneous determination of nitrite and nitrate in natural waters.
一种新的流动注射催化分光光度法被提出，用于同时测定亚硝酸盐和硝酸盐。该方法基于亚硝酸盐对在磷酸介质中结晶紫和溴酸钾之间的氧化还原反应的催化作用，以及硝酸盐在线用涂镉锌还原柱还原为亚硝酸盐。通过测量在 610nm 最大吸收波长处结晶紫的吸光度降低来分光光度法监测氧化还原反应。采用了将还原柱插入采样环的技术，流动注射系统产生了具有肩峰的信号。峰上升部分的肩峰高度对应于亚硝酸盐浓度，峰的最大值对应于硝酸盐加亚硝酸盐。检测限为亚硝酸盐 0.3ngml(-1)，硝酸盐 1.0ngml(-1)。每小时可分析多达 32 个样品，相对标准偏差小于 2%。该方法已成功应用于天然水中亚硝酸盐和硝酸盐的同时测定。
