浮选-诱导显色计时法测定痕量磷

Determination of Trace Phosphorus by Flotation-Timing Visual Colorimetry

用罗丹明B作为离子缔合剂与磷钼杂多酸形成离子缔合物并用苯浮选,利用钼对H_2O_2-I^-体系的催化作用测定钼而间接测定磷。方法的线性范围为2～60ng/mL磷,对5ng/mL、10ng/mL磷标准溶液进行六次测定,相对标准偏差分别为5.6×和4.2%。对天然水样进行测定并进行加标回收实验,回收率86～104%。

A Sensitive method is described for the determination of trace phosphorus in natural water based on the formation and flotation of Rhodamine B-molybdophosphate ion pair and the catalytic effect of Mo(Ⅵ) on the oxidation of iodide by hydroxide. The linear range for phosphorus is 2～60ng/mL. The relative standard deviations are 5. 6% and 4. 2% for 5 and 10ng/mL phosphorus respectively. Recoveries of 86～104% can be obtained.