Universidade Federal da Bahia, Instituto de Química, Campus Ondina, Salvador, BA 40170-290, Brazil.
Talanta. 2012 Aug 30;98:231-5. doi: 10.1016/j.talanta.2012.06.080. Epub 2012 Jul 7.
In the present work, we propose a method for the determination of nitrite based on the chemical generation of nitric oxide (NO) and its detection by high-resolution continuum source molecular absorption spectrometry. NO is generated by the reduction of nitrite in acidic media with ascorbic acid as the reducing agent and then transferred into a quartz cell by a stream of argon carrier gas. The conditions under which the NO is generated are as follows: 0.4 mol L(-1) hydrochloric acid, 1.5%(w/v) ascorbic acid, an argon gas pressure of 0.03 MPa and an injection time of the reducing agent of 4s. All measurements of molecular absorption were performed using the NO line at 215.360 nm, and the signal was measured by peak height. Under these conditions, the method described has limits of detection and quantification of 0.045 and 0.150 μg mL(-1) of nitrite, respectively. The calibration curve is linear for nitrite concentrations in the range 0.15-15 μg mL(-1). The precision, estimated as the relative standard deviation (RSD), was 3.5% and 4.4% for solutions with nitrite concentrations of 0.5 and 5.0 μg mL(-1), respectively. This method was applied to the analysis of different water samples (well water, drinking water and river water) collected in Cachoeira City, Bahia State, Brazil. The results were in agreement with those obtained by a spectrophotometric method using the Griess reaction. Addition/recovery tests were also performed to check the validity of the proposed method. Recoveries of 93-106% were achieved.
在本工作中，我们提出了一种基于化学生成一氧化氮（NO）并通过高分辨率连续光源分子吸收光谱法检测其的亚硝酸根测定方法。NO 是通过酸性介质中亚硝酸根与抗坏血酸作为还原剂还原生成的，然后通过氩载气流转移到石英池中。生成 NO 的条件如下：0.4 mol/L 盐酸、1.5%（w/v）抗坏血酸、氩气压为 0.03 MPa 和还原剂的注入时间为 4s。所有分子吸收测量均使用 215.360nm 的 NO 线进行，信号通过峰高测量。在这些条件下，所描述的方法对亚硝酸根的检测限和定量限分别为 0.045 和 0.150μg/mL。校准曲线在 0.15-15μg/mL 的亚硝酸根浓度范围内呈线性。对于亚硝酸根浓度为 0.5 和 5.0μg/mL 的溶液，精度（以相对标准偏差（RSD）表示）分别为 3.5%和 4.4%。该方法应用于分析巴西巴伊亚州卡舒埃拉市采集的不同水样（井水、饮用水和河水）。结果与使用格里斯反应的分光光度法获得的结果一致。还进行了添加/回收测试以检查所提出方法的有效性。回收率为 93-106%。
