烷基磷酸酯中有效磷的测定

Determination of Available Phosphorous in Alkyl Phosphate

用抗坏血酸-磷钼蓝分光光度法测定烷基磷酸酯中的有效磷。有效磷=总磷-无机磷。考察了检测波长、显色剂用量、硫酸加入量及显色时间等测定条件对测定结果的影响。方法最佳测定条件为：检测波长820nm;硫酸（9.58 mol.L-1）、钼酸铵（60 g.L-1）、抗坏血酸（100 g.L-1）的加入量分别为2.00、2.00、1.00 mL,70℃水浴条件下显色20 min。在该条件下,测定吸光度值与质量浓度呈线性关系,总磷测定回归方程为：A=0.1924ρ＋0.0134,相关系数r=0.999 5;无机磷用正戊醇萃取法测定,回归方程为：A=0.1846ρ＋0.0094,相关系数r=0.999 1。方法回收率为91%~97%,RSD小于3.4%。该方法操作简单、计算方便,有望应用于磷酸酯生产的质量控制。

The available phosphorous compound of alkyl phosphates was determined by ascorbic acid-molybdenum blue spectrophotometry.This compound was total phosphorus minus inorganic phosphorus.The effect of definite wavelength,amount of color reagent,amount of sulfuric acid,color times on definite conditions were as follows：Definite wavelength was 820 nm,amounts of sulfuric acid,ammonium molybdate and ascorbic acid were 2.0,2.0,1.0 mL respectively;the reaction mixture was heated for 20 min in water bath at 70 ℃.Beer′s law was obtained in the range of 0.2 to 10 mg·L-1 between the values of absorbance and concentration of phosphorous.Corresponding to the linear regression equation,the total phosphorus：A=0.1924ρ＋0.0134（r=0.999 5）;Inorganic phosphorus：A=0.1846ρ＋0.0094（r=0.999 1）.The average recovery rate was 91% to 97%,RSD3.40% in the above-mentioned conditions.This method was simple to operate and easy for calculation,which was satisfactory for the determination of effective phosphorus in the alkyl phosphate.