溴酸钾氧化孔雀石绿和甲基橙褪色光度法测定水中亚硝酸根

Dual-wavelength and dual-indicator catalytic kinetic spectrophotometry for determination of trace nitrite

在H3PO4介质中,利用痕量NO2-催化KBrO3氧化孔雀石绿和甲基橙褪色的反应,建立了双波长双指示剂催化动力学光度法测定痕量NO2-的新方法。该反应在最大吸收峰505nm和615nm处,催化和非催化体系吸光度的变化与NO2-浓度呈线性关系,线性范围为0.01～0.80μg/mL,检出限为1.3×10-3μg/mL,该方法用于环境水样(自来水、雨水、延安卷烟厂废水)中痕量NO2-的测定,加标回收率为97%～110.2%.

A new dual-wavelength and dual-indicator catalytic kinetic spectrophotometric method is developed for the determination of trace amounts of NO2 -. It is based on the catalytic effect of NO2 on the oxidation of Malachite Green and methyl orange by potassium bromate in the medium of H3PQ. The absorbances of catalytic and uncatalytic systems were measured at 505 nm and 615 nm respectively. Under the optimum conditions, the linear range of the determination is 0. 01 -0. 80 ~g/mL and the detection limit isl. 3 x 10 -3 p^g/mL. The method has been applied satisfactorily to the determination of NO2-in water samples （tap water, rain water and sewerage of yan＇ an cigarette factory） with recoveries of 97% -110.2%.