在硫酸介质和表面活性剂十二烷基硫酸钠(SDS)存在下,亚硝酸根对溴酸钾氧化亚甲基蓝的褪色反应具有催化作用,并且由于添加了SDS,体系的灵敏度明显提高,据此提出了测定痕量亚硝酸根的方法。亚硝酸根的质量浓度在0.02~1.0 mg·L-1范围内与ΔA呈线性关系,方法的检出限(3s/k)为0.074 mg·L-1。方法用于火腿肠中痕量亚硝酸根的测定,并做回收试验,测得回收率在98.8%~103%之间,测定值的相对标准偏差(n=5)在1.9%~2.4%之间。

In a H2SO4 medium and in the presence of SDS, color-fading of methylene blue by oxidation with KBrO3 was catalyzed by NO2-, and the sensitivity of the color-fading reaction was found higher than that of the reaction in the absence of SDS. Based on these facts, a micelle-sensitized catalytic spectrophotometric method for determination of trace amount of nitrite was proposed. Linear relationship between the magnitude of decrease in absorbance (ΔA) and mass concentration of nitrite was obtained in the range of 0.02-1.0 mg·L-1, with detection limit (3s/k) of 0.074 mg·L-1. In the determination of trace amount of nitrite in sausage sample by the proposed method, values of recovery found by standard addition method were in the range from 98.8% to 103%, with values of RSD′s (n=5) in the range of 1.9%-2.4%.