研究了在H₃PO₄溶液中痕量NO₂^-对H₂O₂氧化中性红的褪色反应有催化作用,催化程度与NO₂^-量线性相关。结果表明,有色溶液的最大吸收波长为530nm,方法检出限为0.014μg/L,催化程度与NO₂^-质量浓度在0～0.080mg/L范围内符合比耳定律,加标回收率为96.0%～106.0%。本法灵敏度高、选择性好、分析速度快,用于城市污水中微量NO₂^-的快速测定,结果满意。

Trace NO₂^- in H₃PO₄ solution has been studied. It catalyzes the decolorization reaction of neutral red (NR) by oxidizing H₂O₂ in H₃PO₄. Its catalytic extent is linear with the contents of NO₂^-. The results show that the maxium absorption wave length of the colored solution is 530 nm. and the detection limits of this method is 0.014 μg/L. When the catalysis degree and NO₂^- content are in the range of 0-0.080 mg/L, it accords with Beer′s Law. The appending recovery rate is 96.0%-106.0%. This method has high sensibility, good selectivity, quick analytical speed. When it is applied to the fast determination of trace NO₂^- in municiple sewage, satisfactory results have been obtained.