以3，5－二溴邻苯二胺为显色剂用分光光度洁测定土壤中微量硒

1, 2-DIAMINO-3, 5 DIBROMOBENZENE USED IN THE DETERMINATION OF SELENIUM IN SOIL WITH SPECTROPHOTOMETRY

以３，５－二溴邻苯二胺（ＤＤＢ）代替常用显色剂，并以Ｈ３ＰＯ４＋Ｈ２Ｃ２Ｏ４＋ＮＨ２ＯＨ·ＨＣｌ取代ＥＤＴＡ作掩蔽剂的分光光度法测定土壤中微量硒。实验选择了测试的最佳条件，包括最大吸收波长，介质酸度，显色剂用量，显色时间，温度，共存离子的掩蔽，萃取效率等。通过对标准样品的测定和工作曲线线性关系的测试，表明本法精密度高，准确度好。对江苏省三种代表性土壤中全量硒和各形态硒的分析，证明该法灵敏，快速，选择性好，简单易行，线性范围广，适用于测定土壤样品中硒含量。

Selenium was determined spectrophotometriclly with 1, 2-dinmino- 3, 5 dibromobenzene (DDB ). Appropriate conditions of measurement were selected, including the maximum absorption wavelength (`λmax ). medium pH, developer amount, temperature, time and stability of the reaction. The interference from Fe and oxidixing agents were masked by H3PO4+H2C2O4+NH2OH·HCl and Se-DDB complex (4, 6-dibromopiazselenol) as measured at 335 um. From the determination of reference samples and the linear relationship of calibration curve, it was indicated that the method was precise and accuracy. The results from total and fractions of selenium contents in soil samples showed that the method was simple, rapid, sensitive, broad in linearity, espeially effusive in determination oftrace selenium in soil.