摘要
将粗硒中硒用还原法预分离后用硫代硫酸钠滴定法测定硒的含量。称取试样0.100 0g溶于硝酸中,加硫酸3mL,蒸发至刚冒白烟。加入盐酸(1+1)溶液100mL,酒石酸1~2g,加热溶解盐类,缓慢加入盐酸羟胺4~6g,于80~90℃下保温1.5~2h后,将还原为单质硒的沉淀滤出。在沉淀及滤纸中加盐酸10 mL及硝酸0.5 mL,并加热使硒单质溶解,加入水100mL,脲2g,煮沸3min,冷却至室温,以硫代硫酸钠标准滴定溶液为滴定剂,在碘化钾存在下,以淀粉溶液为指示剂滴定其硒的含量。取2件实样进行精密度试验,测定结果的相对标准偏差(n=7)为0.22%,0.23%。另以2件实样为基体用标准加入法进行回收试验,测得回收率分别为99.8%,100%。
Na2 S2O3 titrimetry with preseparation of selenium by reduction was applied to the determination of Se in crude selenium. The sample （0. 100 0 g） was dissolved in HNO3 and fumed with 3 mL of H2SO4 until the SO3 fume just evolve. The salts were dissolved by heating with 100 mL of HCl （1＋1） and 1 to 2 g of tartaric acid. Hydroxylamine hydrochloride （4 to 6 g） was added to the solution, which was preserved at 80 to 90 ℃ for 1.5 to 2 h to reduce Se to its elementary state. The mixture was filtered and the elementary Se was dissolved by heating with 10 mL of HC1 and 0. 5 mL of HNO3, and then 100 mL of H2O and 2 g of urea were added, and the solution was boiled for 3 min. After cooling, selenium was determined by titration with Na2 S2O3 standard solution in the presence of KI using starch solution as indicator. Test for precision was made by analyzing 2 samples of crude selenium, giving values of RSD＇s （n=7） of 0. 22% and 0. 23%. Test for recovery was made by standard addition method with 2 crude selenium samples as matrix, values of recovery found were 99.8% and 100%.
出处
《理化检验（化学分册）》
CAS
CSCD
北大核心
2018年第2期209-211,共3页
Physical Testing and Chemical Analysis(Part B:Chemical Analysis)
关键词
硫代硫酸钠滴定法
预分离
粗硒
硒
Na2S2O3 titrimetry
preseparation
crude selenium
selenium
作者简介
李先和（1976-），男，江西宜春人，高级工程师，主要从事化验分析工作;通信联系人。wanjuewan@163．com.
