方波伏安法间接测定饲料中的高含量磷

INDIRECT DETERMINATION OF HIGH CONTENT PHOSPHORUS IN FEED BY SQUARE WAVE VOLTAMMETRY

在pH =5 .5的六次甲基四胺 -盐酸缓冲溶液中 ,硝酸铅与磷酸根和氯离子反应 ,生成磷酸氯化铅复盐沉淀 ,用方波伏安法测定过量的铅离子 ,从而间接测定无机磷。在最佳测定条件下 ,当 0 .0 4mol/L硝酸铅标准溶液的用量为 1.0mL时 ,峰电流ip与磷的质量浓度c在 0 .2～ 2 0 μg/mL内呈良好线性关系 ,线性回归方程为ip=-2 .39c +5 4 .82 ,相关系数为 0 .987 6 ,检出限为 0 .0 85 μg/mL。用于饲料中磷含量的测定 ,测定结果的相对标准偏差为 1.2 4 %～ 2 .4 4 % ,加标回收率为 95 %～ 99%。

In hexamethylenetetramine-hydrochloric acid buffer solution (pH=5.5), the phosphate reacts with lead nitrate and chloride ion to form the precipitation PbCl 2[Pb 3(PO 4) 2] 2·H 2O, a square wave voltammetric method for the determination of excess lead in the solution was set up. The method was used for the indirect determination of phosphorus. Under the optimum conditions, when 1.0 mL 0.04 mol/L Pb(NO 3) 2 standard solution was used, the square wave peak height is linear with the concentration of phosphorus in the range of 0.2～20 μg/mL. The linear regression equation is i p=-2.39c+54.82(r=0.9876).The detection limit is 0.085 μg/mL.This method was used to determine the phosphorus in feed,the RSD is 1.24%～2.44%, and the average recovery is 95%～99%.