基于量子点增敏化学发光同时测定尿液中的亚硝酸盐和硝酸盐

采用铜镉柱还原硝酸盐,与CdTe量子点增敏过氧亚硝酸-碳酸钠体系的化学发光信号相结合,开发了快速在线同时分析亚硝酸盐和硝酸盐的新方法.对流动注射、化学发光等实验参数条件进行优化,在Na2CO3的浓度为0.2 M、H2O2的浓度为0.03 M、Na2EDTA的浓度为1×10-3 M、CdTe量子点粒径为2.84 nm的条件下,过氧亚硝酸-碳酸钠体系可以获得最优的化学发光信号.该方法检测亚硝酸盐的线性范围为0.3~75μM,检测限可达0.12μM,其相对标准偏差为1.9%;硝酸盐的线性范围为1.0~100μM,检测限可达0.26μM,其相对标准偏差为1.5%.此方法无需衍生和分离,可以实现同时、准确、快速和高选择性地检测人体尿液中亚硝酸盐和硝酸盐的含量,回收率分别为94%~105%和96.6%~110.4%.

Simultaneous detection of nitrate and nitrite in human urine using CdTe quantum dot-enhanced chemiluminescence from peroxynitrous acid-carbonate system

In this study, a novel method has been developed for the simultaneous detection of nitrate and nitrite using CdTe quantum dot-enhanced chemiluminescence （CL） from peroxynitrous acid-carbonate （ONOOH-Na2CO3）, coupled with the reduction of nitrate in the presence of copperized cadmium column. The corresponding linear regression equation of nitrite was established in the range of 0.3-75 μM, the detection limit （S/N = 3） was 0.12 μM, and the relative standard deviation （RSD） for seven repeated measurements of 1.0 μM nitrite was 1.9%; the corresponding linear regression equation of nitrate was established in the range of 1.0-100 μM, the detection limit （S/N = 3） was 0.26 μM, and the relative standard deviation （RSD） for seven repeated measurements of 1.0 μM nitrate was 1.5%. Moreover, this proposed method has been successfully applied to detect nitrite and nitrate in human urine with good accuracy and precision. Good agreements were obtained for the determination of nitrite and nitrate in human urine between the present approach and the standard spectrophotometric method. The recoveries were found to fall in the range between 94% and 105% for nitrite, 96.6% and 110.4% for nitrate.