一种批量连续提取沉积物中无机磷的微量测定方法

A large-batch sequential extraction and micro determination of the inorganic phosphorus in sediments

发展了一种批量连续提取沉积物中反应性无机磷的微量测定方法。以2 mL规格的圆底旋盖离心管为提取容器,对沉积物中的弱吸附态磷、铁锰结合态磷、铝结合态磷和钙结合态磷进行提取。利用酶标仪自行建立磷钼蓝微量比色方法测定上清液中磷的浓度,其检出限为3μg/L,RSD在6%以内。同时,使用微量测定法对大沙河湿地、骆马湖等5个研究区沉积物中各形态无机磷的含量进行检测,精密度较好。运用Kruskal-Wallis非参数检验法与常规方法测得的结果进行比较,两种方法无显著性差异。方法为湖泊沉积物中磷形态的获取提供了新的路径。

The measurements of different forms of phosphorus in sediments is of great significance to the study of lake eutrophication.A large-batch sequential extraction and micro determintaion method for the reactive inorganic phosphorus from sediments was presented in this paper based on Hu Jun’s sediment grading extraction scheme.In this method,a 2 m L of rounded bottom centrifuge tube was selected as extraction container to extract the weakly adsorbed inorganic phosphorus(Lab-P),iron and manganese bound phosphorus(BD-P),iron and aluminum bound phosphorus(NaOH-P),as well as calcium bound phosphorus(Ca-P)in the sediments.A micro molybdenum blue colorimetric method was established to measure the concentrations of phosphate in the extracted supernatant by multifunction microplate reader,the detection limit of the method is 3μg/kg and the precision is less than6%.Meanwhile,the contents of each form of phosphorus in the sediments of the five research areas which include Da-Sha-He Wetland and Luo-Ma Lake were detected by the proposed method,and a favorable accuracy was obtained.The nonparametric testing of Kruskal-Wallis was utilized in the significant difference test to compare the detection results with those obtained by the conventional methods,the comparison results showed that there was no significant difference between the two detection results,indicating the proposed detection method is effective and reliable.Comparing with the conventional method,this method greatly reduces the amount of analyte,and the operation is more simple and convenient,additionally,it provides a new path for the acquisition of phosphorus fraction in lake sediments.