流动注射-光度法测定亚硝酸盐

为快速测定微量亚硝酸盐,建立了一种新的测定亚硝酸盐的方法--流动注射-催化光度法.该方法结合流动注射技术,以亚硝酸盐对氯酸钠与亚甲基蓝发生的褪色反应有催化作用的研究结果为基础.最优试验条件下,在5～150 μg/L和150～1 000 μg/L范围内吸光强度与NO_2~-的质量浓度呈良好的线性关系,该方法的检出限为1 μg/L.对质量浓度为10和100 μg/L的NO_2~-分别进行了11次连续测定,相对标准偏差分别为3.1%和4.6%.用此方法检测河水和地下水水样中的亚硝酸盐,标准偏差为1.1%～3.4%,加标回收率为97.6%～100.3%.

Determination of Nitrite with FI-Spectrophotometric Analysis

A new flow-injection catalytic kinetic spectrophotometric method was proposed to rapidly determinate trace amounts of nitrite. The proposed method is based "on the accelerating effect of nitrite on the reaction between potassium chlorate and methylene blue in strongly acidic media and combines the flow injection. Under the selected conditions, the calibration graph is linear in the nitrite mass concentration ranges of 5 to 150 μg/L and 150 to 1 000 μg/L, and the detection limit is 1 μg/L. The relative standard deviation is respectively 3.1% for 10 μg/L nitrite (n, number of samples, is 11) and 4.6% for 100 p.g/L nitrite (n = 11). The proposed method has been applied to the determination of nitrite in natural water samples, the standard deviation is 1.1% to 3.4% and the recovery is 97.6% to 100.3%.